STATE OF CALIFORNIA
EARL WARREN. Governor
DEPARTMENT OF NATURAL RESOURCES
WARREN T. HANNUM, Director
DIVISION OF MINES
Ferry Building, San Francisco 1 1
OLAF P. JENKINS. Chief
AN FRANCISCO
SPECIAL REPORT 8
AUGUST 1951
TALC DEPOSITS OF
STEATITE GRADE
INYO COUNTY, CALIFORNIA
By BEN M. PAGE
Prepared in Cooperation with the United States Geological Survey
Digitized by the Internet Archive
in 2012 with funding from
University of California, Davis Libraries
http://archive.org/details/talcdepositsofst08page
TALC DEPOSITS OF STEATITE GRADE, INYO COUNTY, CALIFORNIA f
By Ben M. Pace *
OUTLINE OF REPORT
Page
__ 3
Illustrations — Continued
\BSTRACT
INTRODUCTION 5
Acknowledgments (5
Location 6
Topography and accessibility 6
Climate, water, and timber
}EOLOGY 7
Llthology 7
Geologic structure 9
Comparative features of individual deposits 9
Physical characteristics 9
Origin 12
Size and shape of ore bodies 13
Reserves 13
MIXES AND PROSPECTS 13
Talc City mine 13
Alliance mine and Irish lease 20
Alliance mine 21
Irish lease 22
White Mountain talc mine 23
Florence mine 27
Trinity talc mine 29
East End mine and Bob Cat claims 29
Frisco talc mine 30
Victory talc mine 30
Viking talc mine 31
White Swan talc mine 31
Lakeview talc mine 31
Blue Stone talc mine 32
Willow Creek talc mine 32
White Eagle talc mine 33
Eleanor talc claim 35
BIBLIOGRAPHY 3",
Illustrations
Plate 1. Surface geology of the Talc City mine, Inyo
County In pocket
2. Geology of B, C, I), and Intermediate levels,
Talc City mine In pocket
3. Vertical sections, Talc City mine In pocket
4. Surface geology of the Alliance talc mine and
Irish lease, Inyo County In pocket
5. Geologic plans and section of underground
workings, Alliance talc mine, Inyo County__ In pocket
6. Surface geology of the White Mountain talc
mine, Inyo County In pocket
7. Geologic cross-sections, White Mountain mine,
Inyo County In pocket
8. Geologic map of adits, White Mountain mine In pocket
9. Geologic map of the South Deposit, Florence
tale mine, Inyo County In pocket
10. Surface and underground geology of the
Frisco talc mine, Inyo County In pocket
11. Geologic map of the White Eagle mine, Inyo
County In pocket
Page
Figure 1. Photo of ceramic insulators made of steatite^. 4
2. Photo of ceramic articles made of steatite 5
3. Index map of steatite deposits 7
4. Photo of Tale City mine 9
5. Geologic map of Talc City mine area 10
6. Photomicrograph of massive dolomite, Talc
City mine 11
Figure i.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
2").
Page
t Published by permission of the Director, U. S. Geological Sur-
vey. Manuscript submitted for publication January 1951.
* Geologist, U. S. Geological Survey.
Photomicrograph of slightly altered silica
rock, Frisco mine ]■_>
Photomicrograph of high-grade steatite from
Talc City mine i;j
Geologic maps and section, East Side work-
ings, Talc City mine 17
Geology of miscellaneous adits, Talc City mine 19
Diagram of parts of West and Central ore
bodies, Talc City mine 20
Photomicrograph of silica rock from Alliance
mine o ()
Photomicrograph of silica rock from Alliance
mine 21
Photomicrograph of steatite from Alliance
mine oj
Cross-section of the Irish lease 23
Photo of White Mountain mine 24
Photomicrograph of silica rock. White Moun-
tain mine 25
Photomicrograph of silica rock. White Moun-
tain mine 26
Map and cross-section of Main adit, South
Deposit, Florence mine 28
Cross-section, Viking talc mine 31
Cross-section, White Swan mine 32
Cross-section, Willow Creek mine 33
Geologic section at main quarry, White Eagle
mine 34
Photomicrograph of talcose granitic rock,
White Eagle mine 34
Sketch section, Eleanor talc mine 35
ABSTRACT
Steatite is exceptionally pure talc suitable for the manufacture
of high-frequency radio insulators and for other exacting uses. It
was a critical mineral during World War II. At the beginning of
the war there was a single major domestic source, the Talc City
mine, Inyo County, California. During the war talc from several
other mines in California, Nevada, New Mexico, and Montana was
utilized as steatite.
California continues to lead in the production of domestic
steatite. All known steatite deposits in the State are in Inyo County.
Talc of near-steatite quality occurs in other California counties,
but has not proved acceptable to manufacturers of high frequency
insulators.
At the end of 1942 the known steatite reserves of Inyo County
were estimated to be only 8(i,7(M) tons and the rate of production was
computed to be equivalent to about 15,(MK) tons annually. Produc-
tion slackened somewhat, and exploration and development since
1942 have revealed substantial tonnages of steatite which tend to
maintain known reserves. The supply of Inyo County steatite is
seriously limited, however.
Many of the Inyo County steatite deposits are geologically
similar in some respects. Limestone is the most prevalent original
rock. Massive dolomite of hydrotbermal origin has replaced the lime-
stone in areas measuring hundreds or thousands of feet in breadth.
Unaltered remnants of limestone occur as "islands" in the tracts
of massive dolomite. Silica rock resembling quartzite also forms
islands in some of the massive dolomite. The talc deposits are com-
monly ragged, elongated, steeply-dipping bodies in massive dolomite
or silica rock. They are of hydrotbermal origin and are generally
localized at lithologic contacts along which some differential move-
ment has occurred, but some are localized by faults or minor shears
within a single rock type. There are various host rocks.
Steatite ore bodies have been formed by the replacement of
massive dolomite at Talc City. East End. Victory, Trinity, and
White Swan mines ; steatite ore bodies have resulted from the replace
meiit of silica rock at Alliance, Irish, Frisco, Viking, and White
(3
Special Report 8
Talc Deposits op Steatite Grade, Inyo County
fountain mines; steatite has replaced limestone at the Blue Stone
nd Willow Creek mines; tale of near-steatite quality has replaced
ranite at the White Eagle mine. Therefore, the steatizing solutions
re not strictly selective in their action, although they show a prefer-
nce for certain host rocks.
INTRODUCTION
"Steatite" in a mineralogical sense means soapstone
•r massive talc, but in present-day industry the word has
. different connotation. In commercial usage and in this
eport, steatite means exceptionally pure talc l suitable
i for use as the principal ingredient in certain ceramic
jodies. Because these bodies are widely employed for
ligh-frequency insulators in radios and other military
ind civilian equipment 2 (see fig. 1), steatite was included
n the list of critical minerals during World War II.
Although steatite has never been adequately defined,
t is generally understood to mean certain varieties of
ale containing less than 1.5 percent CaO, less than 1.5
percent Feo03, and minute amounts only of other chemi-
'al and mineral impurities. The commercial designation
steatite is also dependent upon favorable firing proper-
ties, and satisfactory electrical and physical character-
istics of the final product. 3 Commercial acceptance is
generally contingent, moreover, upon adequate supplies
i)f uniform material, as the dies of the manufacturer are
designed for raw material of constant shrinkage prop-
erties.
Lava-grade block talc is a variety of steatite dis-
tinguished by its suitability for machining. It must be
free of flaws and must not crack during firing. Formerly,
lava-grade block talc was the only type of steatite used
for insulators. Now, however, it is employed only in rela-
tively small quantities for spacers in radar vaccuum tubes
and for other specialized purposes. Since the discovery in
the early 1920 's that pulverized talc could be used for
making insulators, most steatite has been ground before
firing. It is mixed with a binder, and pressed or extruded
into the required shapes. Because of these technical ad-
vances, the definition of steatite does not stipulate blocky
characteristics.
During World War II emphasis was placed upon
the importance of steatite in the manufacture of radio
insulators, and consumption of the raw material was re-
stricted to such purposes. However, steatite is equal, or
superior, to ordinary talcs for many less exacting uses.
Therefore, it has been used during peacetime in the manu-
facture of high-quality paper, cosmetics, insulating cores
for electric stoves, gas burner tips, and many other items.
The consumption of steatite for certain nonessential pur-
poses constitutes a problem in conservation.
Foreign countries, including France, Italy, and
Manchuria, provided much of the steatite-grade talc used
in the United States prior to World War I, when Cali-
fornia became an important producer. During the years
'A good discussion of talc in general, with references, will be
found in Engel, A. E. J., Talc and ground soapstone in Industrial
minerals and rocks : Am. Inst. Min. Met. Eng., pp. 1018-1(141, 1949.
2 Anon., Talc: Ceramic Industry, vol. 32, pp. 38-40, 1949. This
gives other references on the ceramic uses of talc.
3 A Conservation Order of the War Production Board (M-239,
March 28, 1944, as amended, p. 1) imperfectly defines steatite as
follows: " 'steatite talc' means naturally occurring magnesium silicate
both crude and beneficated, suitable for use in the manufacture of
electrical insulators and containing not to exceed one and one-half
percent (1J%) lime (CaO), not to exceed one and one-half percent
<ll%) ferric oxide (FeiOs), and not to exceed four percent (4%)
alumina (AI2O3)."
between World War I and World War II, California
was almost the only domestic source for talc used m
radio ceramics; when the United States entered World
War II, ceramic manufacturers depended upon two Cali-
fornia mines for virtually all their new raw steatite. In
the first part of 194:5, California steatite was mined at a
rate equivalent to 15,300 tons per year. California now
ranks first among the states in steatite production.
Figure 2. Miscellaneous ceramic articles made principally of steatite.
Other western states began to produce steatite dur-
ing and after the war. In 194(i, California yielded 9,600
tons 4 ; Nevada was in second place with 6,000 tons; Mon-
tana was third, and New Mexico reported some produc-
tion.
* For the same year, the California output of talc of all grades
was about 75,000 tons.
Special Report 8
It must be emphasized that the foregoing data apply
only to talc of steatite grade. New York, at present, out-
ranks all other states with regard to non-steatite tale
production.
In 1!)41 the Planning Branch of the U. S. Army
pointed out that steatite insulators were required for all
military radios, and that the domestic production of raw
steatite came largely from a single source, the Talc City
mine in California. At the request of Brigadier General
Ilines, the U. S. Geological Survey and the U. S. Bureau
of Mines undertook a talc investigation which was carried
on during 1942 and intermittently thereafter.
The U. S. Bureau of Mines made partial analyses
and beneficiation tests of talc samples at the Southern
Experiment Station, Tuscaloosa, Alabama, and conducted
some ceramic and electrical tests at the Electrotechnical
Laboratory, Norris, Tennessee. 5 The Bureau of Mines
also made field examinations of some talc deposits, partic-
ularly in the eastern and southern states. Only a small
fraction of the information obtained by the Bureau of
Mines is included in this paper, which is chiefly con-
cerned with the work of the Geological Survey.
The Geological Survey mapped or described all
known domestic steatite deposits and many deposits of
possible steatite grade, most of which are in the western
states. The work was largely done during 1942 under
the direction of G. R. Mansfield, geologist in charge of
the Section of Areal and Nonmetalliferous Geology. A
preliminary examination of the known steatite sources in
Inyo County, California, was made by D. M. Lemmon.
The subsequent field work was done by L. A. Wright and
B. M. Page.
In California 32 talc mines and prospects were
visited. Those which were known to be producing steatite
or probable steatite were mapped geologically, both
underground and on the surface. "Ore" which had been
approved by steatite consumers was not sampled by the
Survey, but certain doubtful or low-grade talcs in the
proved steatite mines were sampled. The IT. S. Bureau of
Mines tested the samples of substandard talcs to find out
whether or not beneficiation was possible. The mines and
prospects in talc deposits of unproved quality were ex-
amined hurriedly.
Acknowledgments
The IT. S. Geological Survey's talc project received
invaluable aid from any persons and organizations.
Lauren A. Wright did half the field work leading to this
report. Several other members of the Survey, including
G. R. Mansfield and D. M. Lemmon, helped in every
possible way. The Geological Survey is greatly indebted
to the Bureau of Mines, particularly to T. A. Klinefelter
and Richard W. Smith of the Southern Experiment
Station. Essential information was contributed by num-
erous mine operators and other interested parties, in-
cluding Franklin Booth, Otis Booth, Henry Mulryan,
P. E. Thomas, W. K. Skeoch, W. A. Reid, Jaines McNeil,
Frank Canal, Roy Coulon, Marlyn and W. E. MacBoyle,
William Bonham, Joseph Ganim, Watson Rich, Wright
Huntley, and many others. The thin sections used in this
study were expertly made by Alexander Tihonravov.
6 Klinefelter, T. A., Speil, S., and Gottlieb, S., A survey of the
suitability of domestic talcs for high-frequencv insulators : I'. S. Bur.
Mines Kept. Inv. 3804, 1945.
Location
Inyo County, in east central California, is the out-
standing steatite province in the nation, in terms of past
and present production. Most known California steatite
is in or near the Inyo Range. A particularly important
part of the area, embracing the notable Talc City mine
and several other deposits, is the upland between Keeler
and Darwin, just south of the Inyo Range proper.
All the proved steatite of California is in Inyo
County, but elsewhere in the state a few talc deposits are
possibly of steatite grade. For instance, some of the talc
in the Ganim mine, Shasta County, has yielded favorable
analyses, but a large part of the material does not satisfy
steatite requirements. 6
Non-steatite talc deposits, such as the tremolitic talc
deposits of the Silver Lake and Death Valley-Tecopa
regions of California, are more numerous and much
larger than the steatite talc deposits, and generally have a
different geologic setting. These enormous talc resources
are most prominent in San Bernardino County and in
eastern Inyo County, 7 and are more widely known than
the steatite ores farther west. Figure 3 shows the location
of most of the steatite deposits in California examined by
the author. The locations of many California talc deposits
are also given in "Mineral Resources for 1922 ", 8 but no
distinction is made between steatite and non-steatite.
Topography and Accessibility
The Inyo Range is a high north-south fault block of
the Basin and Range province. It is bordered on the west
by Owens Valley, and is partly bordered on the east by
Saline Valley. The latter is an uninhabited desert basin,
but Owens Valley has several towns, including Olancha,
Keeler, Lone Pine, Independence, Bigpine, and Bishop.
The steatite deposits in the Inyo Range and adjacent
uplands range in altitude from about 2,500 to 7,000 feet
above sea level. The Talc City mine and nearby talc
properties are in a hilly terrain readily entered by road ;
they are less than 3 miles from the paved highway be-
tween Keeler and Death Valley. Many of the other stea-
tite localities are not so easily reached, however, being
more remotely situated in steep canyons on rugged,
precipitous slopes. These properties are accessible by
rough, steep, winding roads at best. In the Inyo Range,
three aerial tramways have been built to deposits of silver,
salt, and talc, respectively.
Most of the steatite produced in Inyo County is sent
by trucks to a narrow-gauge branch of the Southern
Pacific Railroad. This branch line, which is in Owens
Valley along the western foot of the Inyo Range ter-
minates southward at Keeler ; at Owenyo (16 miles north-
west of Keeler) it is met by the Southern Pacific standard-
gauge track leading to Mojave and Los Angeles.
Climate, Water, and Timber
The Inyo Range is in a desert region which is hot in
summer and cold in winter. Snow impedes the winter
operation of the White Mountain mine, but most of the
other mines are below the zone of heavy snowfall. The
" (Page, B. M., and Wright, L. A.), Talc in the Ganim mine,
Shasta County, California ; U. S. Geol. Survey, Strategic Minerals
Investigation, Prelim. Maps, 1943.
' Wright, L. A., California talcs : Min. Eng., vol. 187, pp. 122-128,
1950.
Diller, J. S., Mineral resources for 1913: U. S. Geol. Survey,
pp. 153, 155, 157-160, 1914.
"Sampson, E., Mineral resources for 1922: U. S. Geol. Survey,
pp. 81-83, 1923.
Talc Deposits of Steatite Grade, Inyo County
•egion is generally dry, and water for several of the
nines is hauled from Owens Valley. There is no timber
l>xcept at the properties which are over 5,000 feet above
;ea level. Juniper and pifion, but no large trees, grow in
iome of the higher areas.
Figure 3. Index map showing location of California steatite and
near-steatite deposits on record in 1942. All are in Inyo County.
Inset gives location of area in outline map of state.
GEOLOGY
A reconnaissance of the Inyo Range is described by
Knopf and Kirk, 9 and the reader is referred to their
paper for a general discussion of part of the area. How-
ever, the talc deposits are not mentioned by Knopf and
Kirk, and the major deposits including those of the Talc
City mine (see fig. 5) lie to the southeast of the terrain
covered in the reconnaissance.
Most of the steatite deposits are associated with three
kinds of rock : limestone, silica rock, and massive dolo-
mite. The limestone, Paleozoic ( ?) in age, is the principal
original rock. The "silica rock" of this report is a
quartzite-like material ; it may be recrystallized sandstone,
or it may be a product of hydrothermal alteration. The
massive dolomite is definitely an alteration product de-
rived mainly from limestone.
The typical areal distribution of the three characteris-
tic rocks is as follows (see fig. 5) : The limestone occurs
" Knopf, Adolph, A geologic reconnaissance of the Inyo Range
and the eastern slope of the Sierra Nevada, California ; with a section
by Kirk, Edwin, The stratigraphv of the Inyo Range: U. S. Geol.
Survey, Prof. Paper 110, 130 pp., 1918.
chiefly as extensive tracts, within which arc large areas
of massive dolomite. The massive dolomite areas contain
"islands" of unaltered limestone, islands of silica rock,
and talc deposits. The massive dolomite is the most preva-
lent rock in the immediate vicinity of the mines.
The majority of the steatite deposits are lenses or
irregular masses in dolomite or silica rock. Much of the
steatite is along contacts between two rock types, but some
is localized by fractures within a single rock unit.
Exceptions to the above generalities include deposits
in which massive dolomite is lacking, or in which silica
rock is absent. Some steatite is associated with various
rocks that are not present at the more typical deposits.
Granitic rocks are exposed within half a mile to 2
miles of most of the steatite mines, and one deposit of un-
certain quality is largely within a granitic host rock.
Lithology
The rocks of the Inyo County steatite areas are un-
correlated units which show some resemblances from
mine to mine. The stratigraphy is not yet understood ; the
age of the sedimentary formations is not known, some of
the rocks are secondary products, and other rocks (e.g.,
the silica rock) may or may not have a stratigraphic posi-
tion. For these reasons, it is impossible at present to give
a columnar section for the various talc deposits. The
lithologic features that are possessed in common are de-
scribed here, and local characteristics and additional rock
varieties will be treated in the descriptions of individual
mines.
Limestone. The oldest rocks in the immediate vicin-
ity of the steatite mines are limestone. The age is probably
Paleozoic, but positive evidence is lacking. Undoubtedly
more than one formation is represented ; however, the
strata have not been assigned to formational units.
Expanses of limestone, extending partly around the
periphery of the principal mine areas, form the back-
ground of most of the talc deposits (see fig. 5). Limestone
also occurs as remnants within the mine areas, where
much of it has been altered to massive dolomite. The sev-
eral lithologic varieties may be grouped into two main
types.
The most prevalent type of limestone, exemplified at
the Talc City mine, is a well-stratified gray rock with
subordinate thin white layers a fraction of an inch thick.
Locally it is slightly fissile, but is not highly jointed. Dur-
ing weathering it develops smooth outcrop surfaces. This
rock is easily scratched by steel, and effervesces vigor-
ously in cold, dilute hydrochloric acid. A few layers con-
tain poorly-defined crinoid (?) fragments, and others
contain minute bits of carbonized plant remains.
A second, less plentiful, type of limestone is dense,
relatively hard, siliceous, and contains dolomitic beds.
This variety is black, weathering to a pale-gray or tan-
gray color, and it commonly contains flint or siliceous
streaks with coarser texture than flint. It is distinctly
stratified in beds :] inches to '1 feet thick, but is not thinly
laminated or platy except where altered. It is scratched
less easily than pure limestone, and efferveces less readily
in cold, dilute hydrochloric acid. The "stratified dolomite
and limestone" of the Talc City mine and the "flinty
dolomitic limestone" of the White Mountain mine are
examples of this type of rock.
Special Report 8
Silica Rock. A silica rock, consisting of quartz and
closely resembling quartzite, is prominent in most of the
Inyo County steatite areas. It forms strong, massive out-
crops. The silica rock is unstratified, and contains no
fossils. It is gray where fresh, but in many places it
weathers dark brown. The brown color is helpful in dis-
tinguishing the rock from the massive dolomite which
commonly surrounds it. The silica rock cannot be
scratched by steel, and when it is struck by a hammer
sparks sometimes are produced.
The silica rock generally occurs in isolated, discon-
tinuous patches of peculiar shapes, within areas of mas-
sive dolomite (fig. 5). Lack of areal continuity and lack
of systematic structural arrangement are the most puz-
zling features of the rock.
Two hypotheses regarding the silica rock are as fol-
lows : (1) At one time it may have been sandstone, which
has since been partly recrystallized. If so, it should prop-
erly be termed quartzite. Or (2) it may be a product of
hydrothermal alteration of dolomite.
The first hypothesis is supported by the fact that
ordinary quartzites do occur in the Inyo Range; an im-
portant example is the Eureka quartzite (Ordovician),
which serves as a marker bed in the range. 10 Some steatite
deposits of the region are clearly associated with ordinary
quartzite, as at the Blue Stone mine (fig. 3). Possibly the
silica rock of most of the steatite deposits is also quartzite.
This possibility is favored by the texture of some, but not
all. of the silica rock; locally the quartz grains are well-
rounded, as in many sandstones.
The main objections to the theory that the silica rock
is quartzite are occasioned by the distribution. The rock
must have been a stratiform sedimentary formation at one
time, if it is quartzite, but obviously it is no longer strati-
form in its typical occurrences. The separate patches of
silica rock cannot be explained as the result of erosion
of a formerly continuous stratum, because the distribu-
tion is as erratic at depth as it is on the surface of the
ground. The field relations cannot be interpreted purely
as a result of faulting, as the requisite faults for such a
theory do not exist. If the silica rock actually represents
former sandstone beds, there are two possible explana-
tions for its present lack of stratiform continuity: (1)
parts of the sandstone may have disappeared by con-
version into dolomite; (2) the sand of the original sand-
stone beds may have been gathered into separate masses
by some process which produced the present scattered
discontinuous bodies of silica rock surrounded by un-
broken dolomite. According to this view, the gathering-up
of the sand, forming isolated masses, was accomplished
before the dolomitization of the bordering rocks, as the
massive dolomite shows no corresponding deformation.
The hypothesis of hydrothermal origin readily ex-
plains the field relations of the silica rock. According to
this hypothesis, hot waters rose upward through the
dolomite and altered it to silica rock. This occurred only
where fractures, temperature, pressure, or chemical con-
ditions were appropriate; therefore, the silica rock was
produced not as a continuous mass, but as a number of
separate bodies. The hydrothermal interpretation is fa-
vored by the lack of bedding in the silica rock, and by the
virtual absence of minerals other than quartz; there are
"' Merriam, Charles W., oral communication.
practically no grains of feldspar on ferromagnesian min-
erals. The texture of some of the rock is in accord with
the hydrothermal hypothesis, as some specimens show
irregularly shaped grains closely fitted together along
intricate boundaries. This is inconclusive evidence, how-
ever.
Silica rock is second only to massive dolomite as a
host rock for steatite. Steatite-bearing silica rock gen
erally occurs as "islands" in massive dolomite. This is the
relationship at the Alliance mine, for example. However,
some of the talc at the White Mountain mine is in silica
rock that is 50 to 100 feet outside the dolomite area.
Massive Dolomite. Limestone has been altered to
massive dolomite in the immediate proximity of the talc
deposits.
The color of the dolomite ranges from white to gray
to black, probably because carbonaceous material in vary-
ing amounts is retained from the original limestone. Out-
crops of massive dolomite are extensive and prominent,
and commonly have harsh, hackly surfaces. The rock
surfaces are criss-crossed by small grooves which look as
though they had been made by the dull edge of a knife.
The grooves are spaced approximately ^ to 1 inch apart,
and are caused by the solution of thin calcite seams that
occupy joints in the dolomite.
The massive dolomite is devoid of bedding, unlike the
limestone of the district, and it contains no remnants of
fossils. It is tougher and harder than the limestone, but
may be scratched by steel. The dolomite must be scratched
or pulverized before it will effervesce in cold, dilute
hydrochloric acid ; however, the numerous calcite seams
effervesce more readily and may be misleading.
The massive dolomite varies in grain size. In many
specimens the grains are barely discernible with a hand
lens. In other specimens, they are easily seen by the naked
eye, and the rock is best described as a dolomitic marble.
The field relations of the massive dolomite point to
a hydrothermal derivation from limestone. The dolomite
areas are partly bordered by unaltered limestone, and the
limestone beds locally terminate against the dolomite
rather abruptly. The relationships cannot be explained by
faulting, as the limestone is not separated from the
dolomite by gouge, breccia, slickensided surfaces, or other
evidence of faults. In places the dolomite has invaded
limestone in tongues and cross-cutting bands, obliterat-
ing the bedding. Within the dolomite areas, islandlike
remnants of unaltered limestone are found. The dolo-
mitized zones are unrelated to topography, open fissures,
or indications of weathering ; therefore, they cannot be
ascribed to the action of meteoric waters.
Massive dolomite is pre-eminent as a host rock for
steatite. Most of the deposits are in, or adjacent to, mas-
sive dolomite. This is illustrated by 12 of the 15 steatite
properties examined in Inyo County. Some of the ore
bodies are completely enveloped by dolomite, as at the
Trinity mine, but some are within islandlike patches of
other rock isolated within the massive dolomite ; the
steatite-bearing "islands" consist of silica rock, stratified
dolomite, or limestone. A few deposits are just outside
the periphery of dolomitized areas.
Other Rocks. Slate and thin-bedded sandstone, in
minor amounts, are associated with the limestone of the
Irish lease (fig. 3), and a small thickness of hornfels
occurs southwest of the Talc City mine (fig. 5).
Talc Deposits of Steatite Grade, Inyo County
Figure 4. View of Talc City mine from the southeast. OH — west
glory hole ; HF — headframe of main shaft ; BA — B level adit.
Granitic igneous rocks are exposed in the vicinity of
some of the talc deposits. Megascopically they appear to
range from granite to granodiorite or quartz monzonite.
Some of the granitic areas near the talc mines are located
as follows : one is between Keeler and Darwin, just south
of the Talc City mine ; another is on the east side of the
Inyo Range just north of the White Mountain talc mine ;
and a very large granitic area, shown by Knopf u be-
tween Independence and Saline Valley, extends to the
White Eagle and Willow Creek talc mines near the north
end of Saline Valley (fig. 3).
The relations between the plutonic rocks and the
other petrologic units are only partly understood, but
Paleozoic ( ?) limestone and hornfels are intruded in some
places (fig. 5). The granitic rocks of the Inyo Range are
probably outlying extensions of the plutonic complex of
the Sierra Nevada. If this is so, their age is probably late
Jurassic or early Cretaceous.
Dike rocks ranging from basalt or diabase to light-
colored felsite occur near the Frisco, Talc City, and White
Mountain mines. The dikes cut across Paleozoic ( ?) lime-
stone and the granitic rocks, and small altered dikes have
been found in the massive dolomite.
Geologic Structure
Folds. The unaltered rocks (chiefly limestone) in
the vicinity of the steatite mines are generally folded. For
example, north of the Talc City mine there is a pair of
tightly compressed synclines, south of the mine there are
several isoclinal folds, and to the east and west of the mine
the beds dip from 50° to 90° (fig. 5). The rocks of some
of the steatite areas show no fold axes, but nevertheless
dip moderately to steeply, and probably represent the
limbs of former folds.
Some folds in limestone have been practically obliter-
ated by dolomitization, the massive dolomite retaining
only a few remnants of stratified limestone. The orienta-
tion of the unreplaced strata indicates the probable pre-
dolomite structure ; this is illustrated at the Talc City
mine.
The major folding in the region occurred before the
emplacement of the granitic intrusions, according to
Knopf, 12 and is probably late Jurassic in age. It preceded,
and may have facilitated, the dolomitization.
11 Knopf, Adolph, A geologic reconnaissance of the Inyo Range
and the eastern slope of the Sierra Nevada, California: U. S. Geol.
Survey Prof. Paper 110. pi. II, 1918.
a Knopf, Adolph, A geological reconnaissance of the Inyo Range
and the eastern slope of the Sierra Nevada, California: t - . S. Geol.
Survey Prof. Paper 110, p. 9, 1918.
Faults. Faults of several ages have been observed
and inferred. They may be classified as: (1 i pre-dolomit*,
(2) post-dolomite and pre-steatite, (3) post-steatite.
Pre-dolomite faults are not positively established,
but are indicated by incomplete evidence. For example,
at the Talc City mine early faulting is suggested by the
apparent repetition of lithologic units that occur as unal-
tered remnants surrounded by massive dolomite. No fault
is visible, but perhaps dolomitization obliterated it, leav-
ing unaltered parts of the hanging-wall block and the
footwall block isolated in the expanse of dolomite. Any
faults which existed prior to the hydrot hernial action
doubtless facilitated dolomitization.
Post-dolomite and pre-steatite faults are important,
as they are occupied and bordered by talc in some places.
They are probably faults of small to moderate displace-
ment (1 to 100 feet?) for the most part, except at the
White Mountain mine, where the displacement may have
been several hundred feet.
Post-steatite faulting on a minor scale is shown by
the sheared condition of most of the talc. This sheared
condition in many places resulted from renewed move-
ment on pre-steatite faults. An exceptional post-steatite
fault of great displacement (thousands of feet?) forms
one boundary of the productive steatite area at the White
Mountain mine, but most of the other mine areas have not
been so strongly affected by post-steatite movements.
Structural Relations of Ore Deposits. 13 Structural
controls are visible or may be surmised in many steatite
deposits. Contacts between rock units have favored the
development of some ore bodies, as at the Talc City mine,
where much of the steatite occurs along the boundaries
between massive dolomite and stratified dolomite or lime-
stone. At the Alliance mine the main ore body is at the
juncture between massive dolomite and silica rock. The
contacts between lithologic units were probably incipi-
ent planes of weakness before the talc was deposited.
Minor differential movement in the rocks was concentrated
at the contacts of adjoining lithologic units.
Faults are likewise effective as structural controls.
Some of the steatite at the White Mountain mine occurs
along a fault between dolomitic limestone and silica rock.
Some minor deposits of the Talc City area are wholly en-
closed in massive dolomite, which appears to have been
sheared or faulted on a small scale prior to the deposition
of the talc.
In some localities, such as the Victory mine, no struc-
tural control of the ore bodies is apparent.
Comparative Features of Individual Deposits
The following table indicates some of the similarities
and differences between the various steatite deposits de-
scribed in this report. One or two near-steatite deposits
are included.
Physical Characteristics
It is generally impossible to distinguish steatite from
other grades of talc at sight, but most steatite has certain
common fractures. It is often possible to judge by the
outward appearance whether or not a material merits
thorough testing. For final identification, a talc suspected
of being steatite must be laboratory tested; analyses
i^The term "ore", which in a strict sense applies to metallic
deposits, is used loosely in this report to designate talc of steatite
quality In this paper "ore deposit" or "ore body" means a mlnable
mass of steatite This usage, although debatable, is well established
in the steatite mines.
10
Special Report 8
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Talc Deposits op Steatite Grade, Inyo County
11
Name of Principal
deposit country rock
Talc City Massive dolomite, silica rock, lime-
stone, stratified dolomite and
limestone
East End Massive dolomite, limestone
Victory Massive dolomite
Trinity Massive dolomite, silica rock
White Swan Massive dolomite
Alliance Massive dolomite, silica rock
Irish Massive dolomite, silica rock, lime-
stone, slate
Frisco Massive dolomite, silica rock, lime-
stone, felsite dikes
Viking Massive dolomite, silica rock
White Mountain Massive dolomite, silica rock, flinty
dolomitic limestone, felsite dikes
Florence Massive dolomite, flinty dolomitic
limestone
Lakeview Limestone or stratified dolomite,
quartzite, diabase
Eleanor Dolomitic marble, silica rock
Blue Stone Limestone, quartzite
Willow Creek Limestone, granite
White Eagle Dolomitic marble, silica rock,
granite
for iron and calcium should be made, and preferably the
aluminum content should also be determined. If the
analysis shows more than 1.5 percent Fe 2 Os, 1.5 percent
CaO, or 4 percent Al 2 0a, the talc is probably not steatite,
although uniform specifications have not been adopted by
manufacturers. Talc which gives satisfactory analyses
should be submitted to steatite laboratories or manufac-
turers for ceramic, electrical, and physical tests before it
can be classed definitely as steatite. 14
Steatite shows the principal mineralogical properties
of talc, 15 of which it is composed. It feels "soapy" to the
touch, is so soft it may be scratched with the fingernail,
and is easily cut by a knife. It is not affected by ordinary
reagents.
Outcrops of steatite are fairly plentiful at the de-
posits, because talc is resistant to chemical weathering,
but the outcrops are commonly eroded flush with the gen-
eral level of the ground because of the softness of the
mineral. Wide deposits of steatite may be topographically
expressed by saddles or depressions.
In most exposures the talc is more closely fractured
than the adjacent rocks. At some places it occurs as thick
leaves or splinters standing on edge.
Where outcrops are lacking, steatite deposits are
locally marked by the presence of talc fragments on the
ground or in the soil ; the pieces of talc, being chemically
inert, tend to accumulate during the decomposition of the
enclosing rocks.
Inyo County steatite is dense, fine-grained, and mas-
sive except for structures caused by shearing or crushing.
It is not flaky, fibrous, or schistose with respect to min-
eral orientation, although in many deposits it is rudely
platy or slickensided because of shearing. Locally the
steatite is highly fractured or pulverized.
" A discussion of requirements and a description of tests by the
U. S. Bureau of Mines is given by Klinefelter, T. A., Speil, S., and
Gottlieb, S., A survey of the suitability of domestic talcs for high-
frequency insulators: U. S. Bur. Mines Kept. Inv. 3804, 1945.
15 For a complete description of the mineralogy of talc, see Dana,
E. S., The system of mineralogy of James Dwight Dana, Cth ed.,
pp. 678-680, 1904.
Rock replaced
by talc
Massive dolomite
Massive dolomite
Massive dolomite
Massive dolomite
Massive dolomite
Silica rock
Silica rock
Silica rock
Silica rock
Silica rock, etc.
Flinty dolomitic limestone,
massive dolomite
Limestone or dolomite ;
quartzite also?
Dolomitic marble, silica rock
Limestone
Limestone
Granite, etc.
Structures
controlling
ore bodies
Contacts and shears
Contact
None visible
Minor fractures?
Minor shears?
Contacts and shears
Contacts and shears
Contacts
Contacts
Contacts, faults
Contacts, faults
Contacts
Contacts
Contact ( s)
Contact
Contacts
Figurk 6. Photomicrograph of massive dolomite, Talc City mine.
This is the host rock for most of the talc. Uncrossed nicols.
The common colors of Inyo County steatite are:
pale gray green, pale green, pale tan green, pale tan,
pale gray, dark gray, gray black, and white. The first-
mentioned color is probably most prevalent. Some steatite
is mottled ; for example, gray and white mottled stea-
tite occurs at the Alliance mine. Steatite is white or nearly
white when powdered, regardless of the original color.
However, raw steatite commonly is not as white as the
non-steatite talcs of the Death Valley-Tecopa region and
other localities.
Much steatite is translucent on thin edges, but this is
by no means diagnostic When scraped with the blade of
a' pocket knife steatite yields a powder that is soft and
smooth to the touch, free of grit, and almost frictionless
when rubbed between the fingers.
Some non-steatite talc shares the above characteris-
tics and cannot be distinguished from steatite except by
laboratory tests. On the other hand, certain kinds of
12
Special Report 8
Table 1
Sample* SiOt AhO, TiO t Fe,0, CaO MgO KNaO Ign, Loss Total
Theoretical 6:1.50 __ __ __ __ 81.7 __ 4.8 100
1-A 62.80 1.98 0.04 1.30 0.64 28.26 0.47 5.25 100.2
1-B 58.06 .85 __ 1.21 .48 81.85 1.14 5.68 99.2
1-C 59.80 1.15 __ 1.25 .08 82.08 .62 5.55 100.03
1-1) 58.70 .68 __ 1.28 .59 82.50 .22 5.98 99.94
1-E 60.05 .45 __ 1.86 .0!) 82.10 .18 5.41 99.58
* The samples came from the following sources: 1-A, probably from Talc City mine; 1-B, Talc City mine; 1-C, White Mountain mine; 1-D, Lenbek mine; 1-E, Talc City mine.
talc contain megascopic impurities that obviously place
them in a non-steatite grade. For example, fine needles
of tremolite or actinolite are commonly seen with the
'aid of a hand lens; or calcite seams or abundant pyrite
cubes may be visible. A very bright or very deep green
color, not merely a pale shade, is also unfavorable, for it
indicates a high chlorite content. Cubes or thick seams of
limonite indicate a non-steatite grade, but thin films of
limonite do not prevent a talc from being classed as
steatite.
Inyo County steatite consists mainly of minute talc
grains, 0.005 to 0.5 millimeter in length. These grains
are anhedral crystals that are mutually unoriented or
locally obscurely oriented (figs. 8 and 14).
Figure 7. Photomicrograph of slightly altered silica rock. Some
specimens have a sandy texture as above. The large grains are
quartz; interstitial material is fine quartz and talc. Specimen from
Frisco mine, near Talc City. Uncrossed nicols.
Sphene occurs sparingly in microscopic grains in
some high-grade steatite, and is commonly accompanied
by leucoxene. Smaller, unidentified mineral specks are
also present. These minerals do not affect the quality of
the ore.
Quartz, representing unaltered relicts of the parent
silica rock, is found as microscopic grains in some of the
acceptable steatite of the White Mountain and Alliance
mines.
Pyrite, limonite cubes, heavy limonite coatings, and
calcite grains and veinlets are undesirable impurities in
some of the ore bodies. Talc containing an appreciable
amount of these minerals is not of steatite grade and
must be sorted out if it is mingled with the steatite.
Calcite from veinlets tends to accumulate in the talc fines
produced during blasting and handling of the ore, so the
fines are seldom of steatite grade.
Partly steatized country rock forms boulders (im-
pure lumps) in many ore bodies, and occurs around the
margins of some deposits. The semi-talcose materials must
be sorted out of the ore.
Manganese oxide dentrites and very thin, local limo-
nite films are commonplace, and a pale-pink coating of
unknown composition is found on steatite in some mines.
These substances are generally not disadvantageous.
The compositions of five commercial steatitic talc
samples from Inyo County, as given by Klinefelter, Speil,
and Gottlieb, 10 are given in table 1. The analyses are
compared with the theoretical composition of pure talc,
H,Mg :i (Si0 3 )4.
Origin
The original rock at the site of the steatite deposits
was predominantly limestone, with a little stratified dolo-
mite. Shale and sandstone were subordinate ; some of the
sandstone may now be represented by the silica rock,
but this has not been proved.
The original rocks were folded — tightly in some
areas — and were fractured and faulted. The structural
deformation assisted the ensuing chemical alteration by
affording fractures and inclined bedding planes along
which solutions could move upward.
Rising hydrothermal solutions penetrated and al-
tered the fractured formations. The solutions did not
come from the granitic material now exposed near the
talc mines, nor from the various dikes, but may have come
from a deeper source related to the visible igneous rocks.
The exposed plutonic rocks themselves have been hydro-
thermally altered in places, as the White Eagle mine,
and so are clearly older than the alteration.
The hydrothermal reagents added magnesium to the
original limestone, changing it into massive dolomite;
the original stratified dolomite was likewise converted
into massive dolomite. If the silica rock represents an
original formation, it too must have been dolomitized
locally; if it was not an original formation, it subse-
quently developed as a hydrothermal product in the
various tracts of massive dolomite. Regardless of the
origin, the massive dolomite contains islands of silica
rock, unaltered limestone, and stratified dolomite. The
hydrothermal changes healed most of the previously
formed fractures, but a second epoch of fracturing oc-
curred. The massive dolomite and adjacent rocks were
sheared in places, and some slippage took place along the
contacts between lithologic units.
Hot waters rose through the rocks, moving along the
fractures and contacts, locally forming talc at a consider-
able depth below the ground surface. The talc was pro-
duced by the addition of water and silica to dolomite,
and by the addition of water and magnesia to the silica
rock. The steatization of the dolomite involved removal
i Klinefelter, T. A., Speil, S., and Gottlieb, S. ( op. cit., p. 11.
Talc Deposits of Steatite Grade, Inyo County 13
is true at the White Mountain mine. Alliance mine, Talc
City East Side ore body, and other deposits. In such
bodies ore boundaries are not distinct.
Reserves
!a£fy -" ' . . I* * s no } advisable to publish reserves of the indi-
vidual steatite properties. In sonic cases the owners are
unwilling to have the data published, in other cases it is
.. : . not known whether the tale is actually of steatite grade,
-\ and as a rule tonnage estimates of steatite deposits are
!• " ■ -. . grossly in error. The ore bodies are not geometrical, they
- cannot be projected with assurance beyond the available
* v •' • ' exposures, the older mine workings are caved and inacces-
sible, and in many properties development is scarcely
j •• kept ahead of mining. For these reasons accurate coni-
j| putations cannot be made.
^^ V % - The total steatite reserves of Inyo County were esti-
\2V O.lm m mated by the writer at the end of 1942 as follows ;
'^V, " Measured 6,000 tons
i ~, Indicated (additional) 32,100
Inferred (additional) 48,600
Figure 8. Photomicrograph of high-grade steatite from Talc City
mine, showing texture. Large dark crystal near bottom of picture is Tot'il oe -/.<• ,
sphene. Uncrossed nicols. - X, >-' IMI f '">*
„ , . , , ,. ., , Al . These figures are, of course, inaccurate. Thev are ex-
of calcium carbonate and carbon dioxide ; and the steati- tremely conservative, and merely denote the order of ma-
ration ot the silica rock involved the removal of some nitude of the rese rves. If the total of 86,700 tons had bee~n
silica to make room for the added constituents. Perhaps correct, and if the rate of mining early in 1943 had been
the hot waters obtained their content of magnesia and maintained, Inyo County steatite would have been ex-
sihca at various depths from dolomite and silica rock hausted in 1948. Fortunately, although some deposits
respectively, and redistributed these ingredients. The were worke d out during the war, the discovery of new ore
vigor of steatizing solutions is illustrated at the White bodies and the f urt her development of old ones tended to
Eagle mine, where granite and other host rocks have been maintain the reserves in much the same wav that known
altered to talc. 1 ' Evidently the solutions were not strictly domestic petroleum resources were maintained during the
selective, although they generally did show a preference past seV eral decades. However, steatite reserves are with-
for certain rock types such as massive dolomite and silica 0U f doubt seriouslv limited
rock.
New or continued hydrothermal activity produced MINES and prospects
disseminated pyrite in some of the talc bodies, which are
therefore not of steatite quality. More shearing also took . . c .' ne
place, and affected steatite and non-steatite talc in nearly v /he ™lc Cl $ mine } s 19 miles by road southeast of
all the deposits Keeler and 6 miles northwest of Darwin, Inyo County,
California, in a group of hills near the south end of the
Size and Shape of Ore Bodies i nvo Range (figs. 3 and 5). Although the area is over
The individual steatite deposits studied in Inyo 5,000 feet in altitude, it is arid and provides neither tim-
County by the Geological Survey are very small to mod- ber nor water for mining. There is no city at Talc City,
erate in size, .containing a few hundred to a few thousand despite the implication of the name. The mine was studied
tons, and are not nearly as large as many talc deposits of by the writer during a period of about 7 weeks in 1942.
non-steatite quality. At the White Mountain mine a Literature concerning the Tale City mine is very
10-year output of about 7,000 tons came from more than meager, although several brief references by Ladoo, 18
half a dozen separate ore bodies. The largest proved Sampson, 19 Tucker, 20 Waring and Huguenin, 21 and others
steatite deposits in California are at the Talc City mine, appear in various books and journals. In the existing ar-
where about 135,000 tons came mainly from two ore tides there is little more than a paragraph or two con-
bodies not depleted by the end of 1942. cerning the geology.
In contrast to the above, some of the non-steatite talc History and Production. The mine was first oper-
of California occurs in deposits that contain from half a ated briefly about 1917 or 1918 under the name of
million to more than a million tons. Simonds talc mine. In 1918 it was purchased from the
In general, most of the steatite ore bodies are elon- ^Udoo, R . B .. Talc and soapstone: u. s. Bur. Mines Bull. 213,
gated lenses Or pods, as much a.S 600 feet in length and pp. 111-117. 1923. Gives geological notes and flow sheet of mill. The
rn j , • ,1 • 1 t i i -l it L . 1, ■ , mining company is referred to as the Inyo Tali Company.
50 teet in thickness. In detail they are highly irregular, ^Sampson, E., U. s. Geological Survey, Mineral Resources for
with rao-opfl outlines fraverl ends offshoots aiul locally 1920, part II, pp. 203-204, 1923. Describes the talc and its technology,
wnn rag^eu outlines, rrd\eu entis, onsnoois, anu locaiij ^Tucker, w. B., California Div. .Mines Rept. it. pp. 300-301,
gradational boundaries. Some steatite deposits contain 1920-21. Gives geological notes. Refers to mine as Simonds Talc mine.
_ -lii e i-i • • 11 1 i 1 Tucker, W. B., California Div. Mines Rept 22, pp. 523-524, 1926,
many residual lumps of the original host rock, and grade Two paragraphs on geology and development.
into cou ntry rock full of talc seams and stringers. This u ^^\ ) ^\f^^^^^S{^^S n t^ ttanam D ' V ' * Mi " es RePt
" Wright, L. A., White Eagle talc deposit: an example of steat- '■" Waring,' C. A., and Huguenin, E., California Div. .Mines Repl
ization of granite: (abst) Geol. Soc. America Bull., vol. 59, p. 1385, 15, pp 126-127, 1919. Report includes a reconnaissance geologic map
1948. of Inyo County.
14
Special Report 8
California Talc Company by the Inyo Tale Company,
which about 1922 became the Sierra Talc Company, the
present owner of the mine and the largest producer of
steatite in the nation. This concern has offices at 5509
Randolph Street, Los Angeles, and mills at Keeler and
Los Angeles. Messrs. Franklin Booth, P. II. Booth, W. H.
Booth, and Otis Booth have served as executive officers
of the company, which is now owned by Mrs. Dorothy P.
Dodds and Mr. Otis Booth. From 1918 to 1942, Mr. W. A.
Reid was mine superintendent at Talc City ; since 1942,
Mr. James McNeil has held this position.
During the first few years of operation, the mine pro-
vided raw material for insulating cores of Hotpoint
stoves. The cores were turned out of block talc, which was
then fired. It was later found that ground talc could be
used for the same products, preventing great waste, and
all the ore is now ground. Much talc from this mine has
been sold to the paper, rubber, and cosmetic industries.
However, manufacturers of electrical insulators for radio
and other equipment began to draw upon the Talc City
production about 1936, and by 1942 virtually the entire
output was used in high-grade electrical ceramics. The
mine is the largest producer of steatite in the United
States, and prior to World War II it was almost the sole
domestic source of radio ceramic steatite.
The Talc City mine is said to have yielded 130,000
tons by early 1942. In 1941 the year's output was 5,800
tons, before the advent of the war-time steatite crisis.
This crisis developed in mid-1942 and strained the ca-
pacity of the 20-year old mine to the limit. The Talc City
mine produced approximately 70 percent to 80 percent
of the nation's wartime steatite supply, an accomplish-
ment which was only made possible by the adoption of
more modern mining and engineering methods.
Mine Workings. The surface of the ground at the
Talc City mine is characterized by large waste dumps
(fig. 4), and by several subsidences where enormous gap-
ing cracks furrow the surface of the ground.
Underground prospecting and development have
been carried out exclusively by driving new workings,
with no geologic mapping (prior to 1942) and with no
core drilling. Geologic studies are now difficult because
most of the older drifts and crosscuts are inaccessible.
Glory holes have been used during the past. The two
largest are the "West" and the "Central"; in addition,
there are the "Evening Star" and the "Ridge" glory
holes (see pi. 1). These were tapped by several adits.
More recent stoping and drifting at deeper levels beneath
the glory holes has caused caving, and at present large
portions of the ground surface and old underground work-
ings are subsiding. In the upper parts of the caved ground
a good deal of country rock has become mingled with the
remnants of talc.
Since the days when talc was removed from glory
holes through shallow adits, a maze of deeper drifts and
cross-cuts has evolved, amounting to several miles of exca-
vation. Not all of these workings are now accessible, but
some are shown on the accompanying maps. There are
two inclined shafts (pi. 1 ). One is on the west side of the
principal hill, and the other on the east side. The west
shaft starts at the A level and leads successively to the B
level (63 feet lower than the collar), the 100-foot level,
the C level (148 feet below the collar), and the D level
(about 255 feet lower than the collar of the shaft). The
shaft continues downward about 50 feet below the D
level. The D level includes extensive workings, which were
largely obstructed by caved talc and country rock at the
time of the writer's field work (1942). According to Mr.
Henry Mulryan, the D level was reopened and was yield-
ing a substantial tonnage of steatite in 1946. Various inter-
mediate levels (pi. 2) are not reached from the main
shaft directly, but are connected by winzes or raises with
the levels enumerated. In addition to the shaft, the nearby
B level adit allows access to the workings (pis. 1 and 2).
The eastside shaft was abandoned for some time and
was reopened in 1942. Drifts branch from it at depths of
58 feet and 94 feet below the collar. The east side work-
ings are now connected with the main workings, but were
separate in 1942.
In addition to the principal shafts and workings,
about a dozen miscellaneous adits and shafts are con-
nected imperfectly or not at all with the rest of the mine.
Operation. The operational history of the mine may
be divided into tw T o unequal parts, the first of which pre-
vailed until the middle of 1942. The second part had just
begun at the end of the writer's field work.
Before 1942, glory holes and underground caving
involved great waste and danger. Occasionally ore was
removed by simply taking out a section of lagging in a
drift, allowing the adjacent broken talc to slide out onto
the floor. More generally, the ore bodies were partly sur-
rounded by workings driven in substantial country rock
that was less likely to collapse; slanting chutes (raises)
were then constructed into the nearby talc. The ore
usually "mined itself" after the stopes reached an
appreciable size, particularly after the ground had been
disturbed by mining at deeper levels. During a period of
months material was drawn from the chutes until broken
country rock predominated over the talc fragments, or
until dolomite "boulders" repeatedly clogged the chutes,
halting the mining at that particular place. Premature
stoping of ore near the D and C levels caused settling and
shattering of overlying ore, and the partial collapse of
drifts and stopes, many of which were not yet worked out.
Afterwards, the talc remaining above the D and C levels
was approached with difficulty.
Since the middle of 1942, during the later operations,
an effort has been nade to avoid caving. In the east side
workings, square sets have been used, and the ore has been
systematically removed.
The talc is trammed by hand from the stopes to
buckets in the shafts. At the surface the ore is carefully
hand-sorted, to eliminate visible calcite, dolomite, iron
oxide, and excessively dark talc. The bulk of the lump talc
is of steatite grade ; the screenings, however, are higher
in lime and are not used for steatite. The steatite is sent
by truck 19 miles to the company 's mill at Keeler, on a
spur of the Southern Pacific Railroad. There the talc is
ground in a Raymond mill with a whizzer air separator on
top, then it passes through a cyclone. Tests for lime con-
tent, color, and fineness are made frequently during each
mill run. The product, which is minus 200-mesh, is sacked
for shipment, representative samples being retained for
reference. All shipments of Talc City steatite are now
ground talc, which is nearly pure white regardless of the
color of the ore. Most of the product is sent by rail to
manufacturers in the eastern states.
Talc Deposits op Steatite Grade, Tnyo County
15
General Geology. The general geologic setting of
the Talc City mine is shown on the sketch map (fig. 5),
and the areal geology at the mine is shown in greater
detail in plate 1.
The talc occurs as irregular, elongated bodies in an
area of massive dolomite. The dolomite is almost sur-
rounded by Paleozoic (?) limestone from which it was
derived by hydrothermal alteration. Within the area of
massive dolomite there are remnants of unaltered lime-
stone, remnants of sedimentary stratified dolomite, and
peculiar "islands" of a silica rock that resembles quart-
zite. A large mass of granitic rock that has intruded the
limestone extends to within 3,000 feet of the mine.
Limestone (Paleozoic?) a'most encircles the mine at
a distance, and small patches of it are present near the
workings (fig. 5 and pi. 1). Most of this limestone is gray,
with a few thin white layers.
A stratified dolomite and limestone, different from
that described above, occurs near the talc deposits (pi. 1).
Its stratigraphic relationships are unknown, as it is prin-
cipally found as isolated patches surrounded by massive
dolomite. There is a marked difference between the charac-
ter of the rock underground and the character on the sur-
face. Surface exposures are distinguished by a tan to gray,
smooth "buckskin" appearance, and by streaks and blebs
of rusty, siliceous material that jut out in relief. Micro-
scopic examination of the stratified dolomite and lime-
stone collected from outcrops shows a sprinkling of coarse
silt and fine sand, largely quartz, in a fine-grained car-
bonate matrix. Underground, the rock resembles shaly
limestone and effervesces freely in cold, dilute acid. It is
much softer, more fissile, and much less dolomitic than
where exposed in surface outcrops. Probably these differ-
ences are caused by hydrothermal alteration near the ore
bodies ; most of the underground exposures of the strati-
fied dolomite and limestone are in the immediate vicinity
of the talc. Many of the workings within this type of rock
have ragged, splintery, somewhat unstable backs and
walls.
A silica rock closely resembling quartzite forms
prominent outcrops at the Talc City mine. It characteris-
tically occurs as isolated, discontinuous patches of peculiar
shapes within massive dolomite (pi. 1), and its strati-
graphic relationships are unknown.
Massive dolomite, utterly different from the strati-
fied dolomite and limestone, is the predominant rock at
the Talc City mine, and envelops or borders the talc
deposits. It is a product of hydrothermal alteration, and
was chiefly derived from limestone ; it forms a tract 2,000
to 3,000 feet wide, and interrupts the expanse of gray
limestone that constitutes the neighboring terrain (fig. 5).
Within the area of massive dolomite are a few patches of
unaltered gray limestone, tan stratified dolomite and
limestone, and silica rock. The massive dolomite is devoid
of stratification, has harsh, hackly outcrop surfaces, and
ranges in color from pale gray to gray black. The single
specimen tested by the writer was iron-free. The rock
consists of subhedral to anhedral dolomite grains which,
in most samples are 0.015 to 0.05 millimeter in diameter
(fig. 6). The texture is coarser in the northeastern parts
of the B level and C level of the mine, and these coarser
facies are best described as dolomitic marble.
Diabase occurs in three or four very small dikes
within the mine area. The dikes are from 2 inches to 2
feet thick, and are quite irregular, having filled branch-
ing joints in the massive dolomite. The word "diabase"
is loosely applied here, as the original texture and min-
erals can only be surmised. Most of the rock is altered to
a soft, fine-grained, dark-green material that disinte-
grates like shale in the open air. The best-exposed dike
may be seen at the mouth of the A-level adit; near the
main hoist house. This dike shows a relict flow structure
and amygdules of quartz and calcite. The chief mineral
is matted, fine chlorite, with talc and some kaolinite ( ?).
There is a sprinkling of microscopic pyrite and limonite
specks, and a few minute grains of sphene.
Outcrops of granitic rock (granodiorite?) are within
3,000 feet of the Talc City mine (fig. 5). This rock is
exposed over a large area ; it is cut by many basalt dikes.
The granitic rock is bordered by hornfels in places, but
elsewhere it has intruded limestone of the type that is
found at the Talc City mine.
Geologic Structure. Folds, and perhaps a major
fault, existed at the site of the Talc City deposits before
the hydrothermal alteration of the rocks took place, but
these structures have largely been effaced by dolomitiza-
tion. The limestone that partly encircles the mine is
strongly folded ; the steeply dipping strata strike toward
the mine, but are obliterated at the edge of the dolomitized
area. Within the area of massive dolomite, the isolated
patches of gray limestone and tan stratified dolomite are
unaltered remnants of formerly continuous formations.
The strata composing these remnants follow two trends
(pi. 1). In the southern part of the mine area the strike
of the remnants varies only a few degrees from north,
but in the northern part the strike is west-northwest. The
elongated talc bodies reflect imperfectly the strike of the
neighboring stratified remnants, hence the talc also shows
two dominant trends. These two trends were probably
inherited from the strike of beds on two limbs of a fold,
or on two sides of a fault.
The existence of a pre-dolomitization fault is also
suggested by the repetition of lithologic units at the West
ore body and the Central ore body (pi. 1). The arrange-
ment and lithology of silica rock and stratified dolomite
and limestone is almost identical in these two parallel
ore bodies. Perhaps faulting of an inclined series of strata
brought two formations into position side by side ; dolo-
mitization then obliterated the fault and engulfed all but
the present remnants of the original formations.
Post-dolomitization faults of small to moderate dis-
placement are present. Faulting has produced conspicu-
ous effects within and along most of the larger talc bodies.
Much of the talc was formed by replacement of wall rock
along faults and subsequent mechanical movements have
largely been concentrated in the ore bodies which are
physically very weak, rather than in the strong country
rock. Consequently countless, interlacing slickensided
surfaces within some of the talc masses give the illusion
that slippage has amounted to thousands of feet.
The movements that produced such pronounced
effects in the talc yielded a few small, inconspicuous
shears only in the massive dolomite. Most of the shears in
dolomite are marked by an inch or two of gouge and
breccia; some are bordered by silicified and sparsely pyri-
tized zones. Some show solution effects of ground water,
which has utilized them as channels, making some of the
fissures as wide as 3 feet.
16
Special Report 8
Some shears in the dolomite are not parallel with
the ore bodies. Most of these are of little importance and
are not traceable for more than 100 feet, but a possible
exception is a fault ( ?) called the "Watercourse" which
is said to terminate the Central ore body. The under-
ground workings at the ' ' Watercourse ' ' were inaccessible
at the time of the mapping.
Breccia zones poorly defined in comparison with the
distinct shears, were noticed in the massive dolomite in a
few places near the mine. They are mostly recemented
with calcite. Some of them are linear, and others have no
geometrical form, but none of them show fault surfaces.
Large-scale phenomena of a different sort occur a quarter
of a mile south of the mine, and also half a mile east of it.
Here breccia in zones over 150 feet wide resembles a
coarse mosaic, in which well-separated fragments of gray
dolomite are bound together by white calcite. There are
no distinct borders or fault surfaces along the zones.
The Talc. The Talc City ore is fine-grained, with
no megascopic flakes, needles, or fibers. Some of it is
highly sheared and slickensided, but some is less dis-
turbed and is moderately massive when first opened up
in the mine ; upon exposure,- incipient cracks open up and
often produce a crude, irregular platy structure. The talc
is softer than the fingernail but is quite brittle. Thin
edges are translucent. Pale gray green, with or without
a tinge of tan, is the typical color of the best steatite but
some of the talc is dark gray and some is dark brown.
The darkest varieties are said to contain more iron and
alumina than the light-colored material, and most of them
are not steatite.
Megascopic impurities in some of the talc include
limonite cubes that range from pin-point size to one-
eighth inch, veinlets and coarse chunks of calcite, and
inclusions of dolomite or partly altered limestone country
rock. Talc containing these substances is sorted out. More
commonplace but less serious are thin stains of iron oxide,
which do not contribute appreciable amounts of iron
unless very abundant. Some thin dendritic films of man-
ganese dioxide are also found, but these are not harmful.
The run-of-mine ore is of steatite quality, and some
of the select material is exceptionally pure. The follow-
ing analyses, kindly furnished by the Sierra Talc Co.,
are representative of the quality being shipped as steatite :
Loss
SiO, MgO AW, CaO Fe,Oj Alkalis on ign.
Sierramie #1 __ 50.61 30.01 1.65 0.84 0.92 0.26 5.04
Sierra
Hi-Grade #1 __ 60.56 30.19 1.46 0.80 0.00 0.22 5.68
The accompanying photomicrograph (fig. 8) shows
one mineral impurity only, a minute crystal of sphene.
Other specimens of the talc show sparse microscopic
specks of sphene, leucoxene, and an unknown mineral
that occurs in extremely small equant grains of low relief.
The steatite is essentially an aggregate of microscopic
matted talc flakes, shreds, and stubby slivers, the last
mainly showing a length-to-width ratio of 2 :1 or 3 :1.
Most of the grains are only 0.005 to 0.025 millimeter long,
and most are anhedral to subhedral. There is no obvious
preferred orientation of the bulk of the tiniest flakes, but
the larger grains exhibit one or two directions of imper-
fect parallelism. Some of the largest flakes and shreds
(about 0.5 millimeter long) occur at random, but others
form continuous, ill-defined, crooked streaks with the
talc crystals oblique to the borders of the streaks. A few
of the larger shreds are in splotches with a subradiating
arrangement. The writer has not seen any relict textures
inherited from earlier minerals. Many non-steatite talcs
show remnants of tremolite, but the Talc City ore does not.
Occurrence. The geologic relationships of the talc
are illustrated in the accompanying maps and sections,
figures 9 and 10, plates 1-3. Without exception the talc
is associated with the massive dolomite. Some talc is in or
next to the residual islands of sedimentary rock sur-
rounded by dolomite, but some is in the massive dolomite
itself. Most or all the talc of steatite grade has been derived
from massive dolomite.
More specific ore controls include the following : (1)
Contacts between massive dolomite and stratified dolomite
or limestone, (2) shears, and to some extent joints, within
the massive dolomite, and (3) contacts involving the silica
rock. Significant quantities of talc are found in places
where only one of these three features is present, but all
three ore controls are evident along parts of the large
Central ore body.
The talc deposits are elongated, narrow, ragged, and
irregular in plan and cross section. In a general way they
dip steeply toward the southwest. Some have definite
hanging walls or footwalls with polished and grooved
surfaces, and with thick talc gouge. "False walls" are
commonplace where the ore has been sheared and slicken-
sided internally. Some talc masses have no distinct hang-
ing wall or footwall; some have not even a moderately
regular boundary, and in some masses, the contact with
the country rock is gradational. Most of the ore bodies
contain at least a few "boulders" (rounded inclusions)
of dolomite.
Some large offshoots containing hundreds of tons of
talc extend from the main bodies at unpredictable inter-
vals. In contrast to the large offshoots, thin stringers of
talc branch from the main talc masses, following joints;
they rarely widen out into another ore body. On the other
hand, stringers of talc within well-defined shears in a
few places do lead to ore bodies. Even locally barren shears
may serve as a possible guide to talc. One such shear,
which is barren on the east side of the main ridge, may
be followed to the Evening Star ore bodv on the west side
of the hill.
The occurrence of talc along contacts between mas-
sive dolomite and stratified dolomite and limestone re-
quires special mention. The talc frequently grades into
country rock on the side towards the stratified material.
As a rule there is an intermediate zone of "semi-talc,"
which may be scratched with the fingernail but which
effervesces in acid, evidently being an intergrowth of talc
and calcite. Within certain layers of this partly altered
rock, true talc occurs in intermittent lenses a few inches in
length. The talc in and near the stratified country rock
is commonly dark brown and has stains of iron oxide, but
the talk adjacent to the massive dolomite country rock
is generally light-colored ore, is practically free of iron,
and is of steatite quality.
Principal Ore Bodies. Although there are perhaps
a score of talc deposits at Talc City, most of the produc
tion has come from three or four. Most of the others are
quite small. In this report the westernmost large deposit
(see map, pi. 1) is called the West ore body, the next one
Talc Deposits of Steatite Grade, Inyo County
17
VERTICAL SECTION THROUGH SHAFT
El. collar 996.7 ft.
-'\ 94- FOOT LEVEL
\ \
\ \
> 1
\
£"'
\ nvl i
El. collar
996.7ft
Gently inclined raise,
approx. 30 ft. above
drift of upper end
Dolomite
PfdfH
Stratified dolomite,
limestone
T40
Contact
(Dashed where
approximately located)
$50
Fault or Shear
showing dip
(Dashed where
approximately located)
Strike and dip of beds
■^30
Variable dip
a
Shaft at surface
K
Shaft going above
and below levels
m
Bottom of shaft
Foot of raise
or winze
Head of raise
or winze
50
ioo Feet
Figukb 9. Geologic maps and section, Kast Sid., workings, Talc I ity min<
18
Special Report 8
to the east is called the Central ore body, and the deposit
at the East Side shaft is the East Side - ore body. A few
hundred feet north of these is the Evening Star ore body.
The West and Central ore bodies show a remarkable
similarity in trend and geology, as indicated on the map.
It might be supposed that they represent a single original
deposit faulted into two segments, but this is not so. The
country rock may have been repeated by faulting, but if
it was, the faulting occurred before the talc was formed.
The conjectured fault must' have been a pre-dolomitiza-
tion structure, as no vestige of such a feature in the mas-
sive dolomite is now exposed.
The West and Central ore bodies have yielded the
larger part of the Talc City output. Widespread caving
has made it impossible to trace all the former outlines of
the ore accurately, but Mr. W. A. Reid obligingly added
his recollections to the writer's piecemeal restoration. In-
tact remnants of talc still afford a good deal of first hand
information.
The West ore body is said to have been exploited
first, and was once considered worked out. It was mined
largely by means of three glory holes. On the surface the
talc comprised an elongated zone 550 feet long, between
massive dolomite and stratified dolomite and limestone.
Patches of silica rock of the hanging wall terminate at a
shallow depth (pi. 3), probably having been altered to
massive dolomite ; the ore body also terminates at a rela-
tively shallow depth at the localities explored to date.
Only two downward prolongations of the ore were en-
countered at the B level. One of these was part of a wide
bulge, and it had various offshoots. The bulkiest portion of
the West ore body at the B level is said to have measured
40 by 60 feet in plan, but in many other places the width
was only 5 or 10 feet. It is quite probable that additional
undiscovered prongs of ore extend to depth south of the
present B-level workings, but that region has not been
explored. The writer believes that downward "roots" of
the West ore body occur like the roots of a tooth. The
south end of the ore body has moderately regular walls
near the surface and dips steeply westward ; the irregular,
wide north end apparently was steeply inclined toward
the west also. Although most of the northern portion is
worked out, part of the southern half of this ore body was
being mined above the A level at the close of 1942.
The Central ore body (pis. 1-3 and fig. 11) is more
persistent at depth than the West body, but is otherwise
similar. Although the heart of the deposit has been mined,
this body is not worked out, and its ultimate depth is not
known with certainty. The Central ore body extends at
least from the surface to the workings below the D level,
a vertical distance of almost 400 feet. According to re-
ports, a crosscut 50 feet below the D level disclosed steatite
ore ; here again it is very likely that downward extensions
occur discontinuously along the strike, and some of these
probably reach below the present workings. On the sur-
face this talc-bearing zone is 680 feet in length, but some
parts are so narrow they cannot be mined. The southern
part of the Central ore body lies between massive dolo-
mite (the footwall), and stratified dolomite and limestone
(the hanging wall). These relations prevail from the
ground surface to the I) level. The northern part of the
Central ore body lacks a stratified hanging-wall formation
--' Not to he confused with the Bast End talc mine less than a
mile away.
at the surface and at the B level, but the stratified dolo-
mite and limestone are present at the C level. The mass of
stratified rock adjacent to the ore evidently plunges north-
ward, so it extends much farther north within the mine
than it does on the surface. Therefore it is possible that
the talc deposit itself will have a greater length under-
ground than on the surface. The northern part of the ore
body, as now exposed, consists of a shear zone incompletely
occupied by talc that in places is only a few inches thick,
but which swells out locally to 5 or 10 feet. This northern
part of the Central ore body is nearly vertical at the sur-
face, but dips to the west at depth (pi. 3) ; it was being
re-explored on the C level in 1942. The southern half of
the Central ore body is thick in places, a width of about
40 feet being reported at one crosscut that is now caved.
Large, irregular, intricate offshoots of talc occur in the
massive dolomite footwall, and some of these can be mined.
The East Side ore body may possibly be a branch or
a faulted segment of the Central talc deposit. The "water-
course" (open fault?) which is said to terminate the
Central body, lies between the two deposits in the mine.
However, on the surface of the ground no evidence sup-
ports the faulting hypothesis.
The East Side ore body is inconspicuous at the ground
surface. Underground exposures show that it is an ill-
defined, elongated lens with many inclusions of country
rock (fig. 9). It dips 42°-62° SW, is 2 to 15 feet thick,
and in late 1942 was developed for more than 180 feet
along the strike and 100 feet down the dip. The stratified
rocks of the hanging wall contain thin streaks of talc,
making the west boundary of the ore rather vague. The
footwall boundary is even less distinct, as talc containing
dolomite inclusions grades into dolomite with interlacing
talc stringers.
The fourth ore body has been mined at the Evening
Star glory holes (pis. 1 and 3) . The talc that was first pro-
duced from this ore body was not considered entirely
satisfactory for steatite, and about half of it was rejected
because of limonite cubes and stains. However, after 1942
acceptable steatite was mined from the deposit. As in the
occurrences described above, the Evening Star ore body
is bordered by massive dolomite on one side, and by strati-
fied dolomite and limestone on the other side. Silica rock
is present also. The talc-bearing zone is not as linear in
plan as the other three ore bodies except at the west end,
which is a steep shear containing only a foot or so of talc.
The eastern end of the Evening Star ore body is in part a
bulge on the same shear, but the major mass of talc is a
stubby branch. The ore body was formerly said to extend
downward as a funnel to a depth of only 40 feet below
the surface, but this has been disproved by exploration
since 1942. Mr. Henry Mulryan states that a wide con-
tinuation of the deposit has been found at depth. At the
surface, the ore ends toward the east against an almost
unbroken barrier of massive dolomite, but, juding from
the West ore body, the subsurface extent of the Evening
Star deposit will prove to be quite different from the
extent on the surface.
Probable Downward Continuation of Ore Bodies.
Because the neighboring limestone in the vicinity of the
Talc City mine may be an ancestral rock without which
the talc might not have developed, the former downward
extent of the limestone is of importance. The remnants
of limestone all dip steeply and have very little curvature,
Talc Deposits op Steatite Grade, Inyo County
19
25
TRUE NORTH ^
kIS
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o
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o
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s o ^
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S Zi O
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o
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20
Special Report 8
indicating that the limestone once extended downward a
great distance: the massive dolomite derived from it is
probably likewise vertically persistent, comprising a
great volume of rock suitable for the formation of talc.
If the granitic rock exposed to the south extends beneath
the Talc City mine at depth, the upper surface of the
underlying granite may be one of the limits of the talc-
bearing zone, but its general position at present can be
inferred only. The massive dolomite is not noticeably
coarser at the C level than at the H level, offering no indi-
cation that an igneous intrusion is very close. Similar
negative evidence is afforded by the lack of lime-silicate
minerals in the massive dolomite. Pyrite, and limonite
pseudomorphs after pyrite, are numerous in some of the
deepest ore now exposed, but they are equally prominent
in some of the talc at the surface of the ground. Finally,
relatively few dikes are found in the mine, but dikes are
plentiful near the granite contact half a mile south of
Talc City. These conditions seemingly indicate that the
upper surface of the granite has not been closely ap-
proached by the mine workings.
The foregoing facts do not demonstrate that talc will
extend downward indefinitely, for temperature and pres-
sure conditions and other factors undoubtedly played an
essential part in the control of ore formation. However,
it is likely that ore occurs at least a hundred feet, and
probably several hundred feet, below the present work-
ings.
E X PLANATION
Ore body ot surface
Ore body ot B level
Ore body ot C level
Feet approximate
,->.->
Figure 11. Generalized diagram of parts i>f the West ore body and
Central ore body. Talc- City mine, showing variation In shape with
depth. Composite map based on Incomplete data. 1 !» 4 2.
•^«r
Figure 12. Photomicrograph of silica rock from the Alliance ]
mine showing sand ( ?) grains of quartz with later rims of chlorite. ,
Incipient mylonitization is indicated. The braided black streak
bisecting the picture is a micro-shear zone, consisting of coherent I
pulverized matter. This rock is the host rock for talc in the
Alliance mine. Uncrossed nicols.
Alliance Mine and Irish Lease
The Alliance mine and Irish lease are on adjoining
claims slightly more than half a mile north of the Talc
City mine, and 6 or 7 miles northwest of the city of Dar-
win. They are about 5,300 feet above sea level, and are i
reached by road from Lone Pine and Keeler. Lauren A.
Wright and the author studied these properties during
a period of 4 days in December 1942.
The Rocks of the Area. The areal distribution of
the rocks is shown in figure 12. Limestone, dark gray and i
distinctly stratified, occurs in the south part of the map
area. Poorly preserved crinoid fragments were found in
some places. Outcrops are gray to buff, and are numerous !
but not very prominent. Most of the limestone underlies
sandstone and slate, described below, but some is also]
found above the slate.
Sandstone, thin-bedded and in part shaly and red-'
dish, overlies the main mass of limestone in at least one
place on the Irish lease. Tt is only 5 or 10 feet thick, and
is included with the slate on the geologic map.
Slate, mainly dark gray or greenish gray, overlies (
the thin sandstone member along the southern border of |
the map area. Slate or other argillaceous material prob-j
ably once existed in other places at the site of the Alli-
ance mine, as some of the profoundly altered rocks in and
near the workings are dark and rich in alumina. One 1
such altered rock, although granulated almost beyond
recognition, appears to have been a silty argillite ; it is [
exposed near the footwall of the talc deposit near the!
Palmers' new shaft.
Massive dolomite is the most abundant rock in the'
northern part of the map area. For the most part it is:
devoid of bedding and is everywhere barren of fossils. I
It is fine to medium in grain size, compact, and tough.
Outcrops are plentiful; they vary from pale gray to buff
and gray black, and exhibit harsh surfaces with tiny j
projections and depressions. The massive dolomite is a
hydrothermal alteration or replacement of limestone.)
Near the talc some of the dolomite lias been changed to
soft, white, non-talcose substance.
Talc Deposits of Steatite Grade, Inyo County
•21
Silica rock forms the central part of tlie mine area
and is topographically the most prominent material,
appearing in numerous bold outcrops which weather
brown. Its contacts with dolomite are very sharp in many
places. Probably the silica rock is a quartzite, as locally
indicated by rounded to subangular "rains of moderately
uniform size (fig. 12), but some specimens contain closely
fitting quartz grains with mutually embayed boundaries
(fig. 13).
Interesting alteration products in the silica rock are
associated with the Alliance talc deposit. Initial petro-
graphic study points to the silica rock as the original
material in most places. The quartz was sheared (fi»-. 12)
and mylonitized in places, and was then hydrothermally
altered. The resulting rock is much darker than the un-
affected silica rock, and in fact bears scarcely any mega-
scopic resemblance to it. The altered rock is dark gray,
in some places tinged with dull green, and may be
scratched with steel. In it are residual quartz grains,
which commonly predominate over the other constituents,
but are somewhat masked by them. Some of the quartz
grains are "frayed", having been partly chloritized.
Chlorite aggregates encircle these frayed grains, and fine
chlorite mosaics are also localized in rounded areas. The
finest constituents of the rock bave not been determined,
and the composition of the wispy, black, mylonitic streaks
is unknown.
A further, or perhaps parallel, alteration of the
silica rock has produced most of the talc at the Alliance
mine.
Figure 13. Photomicrograph of silica rock from the
mine, showing incipient development of talc, which has
the quartz grain-s.-Crossed nicols.
Geologic Structure. The most important structural
relations are those of the central mass of silica rock, which
is apparently bordered by faults both on the south and
on the northwest, as explained below. Talc occurs along
both of these fractures. The Alliance mine is on the north-
west fault, whereas the Irish lease is on the south fault,
South of the silica rock, the limestone and slate dip
northward against the main mass of silica rock (fig. 15).
Therefore a fault exists along the discordant contact,
unless the silica rock is an alteration product of the lime-
. 1 m m
Figure 14. Photomicrograph of steatite from the Alliance mine. The
only mineral shown is talc, but tun or three other minerals occur in
minute quantities elsewhere in the specimen. Uncrossed nicols.
stone and slate strata which run into it. The fault, if such
it is, was formed prior to the hydrothermal activity that
produced talc along the border of the silica rock, and is
now completely healed.
The northwest edge of the silica rock is bordered by
soft altered rocks and by talc, beyond which is massive
dolomite. The soft altered rocks have developed along an
east-northeast shear, and some renewed displacement has
occurred. Slickensided surfaces are widely distributed in
the altered rocks, but the most persistent plane of move-
ment is that which forms the hanging wall of the principal
talc zone; this fault surface dips gently northwest, away
from the silica rock, and passes beneath the massive dolo-
mite.
Elsewhere, the bonier of the silica rock is not a fault
contact, although many portions are relatively straight
and decidedly discordant with respect to the strike of the
nearest stratified rocks. No gouge, breccia, slickensides,
or shears are present ; the silica rock and adjacent massive
dolomite are not separated by so much as a single crack in
many places. The outline of the silica mass is well exposed,
and its shape shows that faulting or at least post-altera-
tion faulting cannot account for the strange shape and
distribution of the silica rock.
Alliance Mine
Ownership and History. Mrs. Edith Lockharl and
George Koest of Darwin, California, are the owners of the
Alliance mine, but lessees have carried on all operations.
The Sierra Talc Company worked the deposit in 1939;
subsequently M. C. Williams has been the lessee. Mr.
Williams operated the mine in 1940-41, then sub-leased it
to the T. S. Diatom Company in 1941-42, and to the Pal-
mer Development Company in 1!I42. The latter company
achieved the largest share of the total production, which
is estimated to have been slightly over 4. .">(>() tons by the
end of 1<)42. Probably at least hall' of this tonnage was
sold for radio ceramic steatite.
Mini Workings ami Opt ration. The surface work-
ings are shown in plate 4. The large open pit undoubtedly
was the site of earliest operation. In pari the pit was
worked as a glory bole, tapped by shallow adits.
22
Special Report 8
An inclined shaft near the glory hole extends to a
depth of 70 feet, and two levels connect with it (pi. 5),
one at 45 feet and one at 70 feet. Most of the 45-foot level
is now inaccessible. The workings at the 70-foot level com-
prise about 450 feet of drifts and crosscuts. Prom these
there are several raises and large, gently dipping stopes
that have been supported in places by square sets but
which more generally have been allowed to cave. Rem-
nants of an inclined winze may be discerned on the 70-
foot level (pi. 5). This winze is said to have been sunk 40
feet in ore.
The talc, in 1942, was sorted at the mine into two
grades "black" and "white," and sent by truck to
Keeler. Here the dark variety was shipped by rail for
milling, but the light was bought and milled at Keeler by
the Sierra Talc Company. The light-colored talc was used
in electrical ceramics, but the dark talc was used for other
ceramics and for fillers.
The Ore Zone. There is no single all-inclusive mass
of talc at the Alliance mine, but if semi-talcose rocks are
included there is a principal ore-bearing zone (pi. 5).
This ore zone has formed along a system of shears ; it lies
between the main body of silica rock and the adjacent
expanse of massive dolomite, and it dips gently northwest
beneath the dolomite.
The soft hydrothermal products in the ore zone form
a belt about 30 feet thick, and include dark-gray chloritic
substances derived partly from silica rock and partly
from slate or argillite, light-colored, softened, semi-talcose
silica rock, and nearly pure talc.
The talc has few distinct boundaries. It appears and
disappears by gradation within the altered zone. Unlike
the talc of the Talc City mine, it has been formed as a
replacement of the silica rock. Well-defined masses or
lenses of talc can rarely be found, as there is a general
erratic blending of talc and semi-talc. However, shapeless
masses of talc large enough to permit mining are en-
countered commonly. The one distinct boundary of the
talc-bearing zone is its fault contact with the massive dolo-
mite of the hanging wall.
Nature of the Talc. There are two varieties of ore,
the light-colored and the dark. The light-colored talc
varies from white to gray, and is frequently mottled ;
the dark talc is dark gray to black. Both types are some-
what blocky, but are cut in all directions by many in-
cipient cracks. There is no schistose, platy, flaky, or
fibrous texture visible to the naked eye. The grain size is
very fine (fig. 14), most of the talc particles being 0.005
to 0.02 millmeter long. Numerous pseudo-spherulitic
clusters of subradiating grains are about 0.04 millimeter
long. These are not shown in the photograph. Some of
the clusters are elongated and some are composite, and
in places they almost touch one another. The only min-
erals other than talc noted by the writer were a few small
grains of sphene, a trace of leucoxene, and extremely
small equant specks of low relief.
The talc is translucent on the thinnest edges only.
Color is of no assistance in distinguishing the ore from
associated semi-talcose rocks, and about the only simple
criteria are "soapy feel" and softness of the talc, in com-
parison with the adjacent materials.
The light-colored talc, which probably constitutes
30 percent to 50 percent of the ore in the Alliance mine,
is steatite used for radio electric ceramics. It has been
analyzed by the Bureau of Mines, which very kindly pro
vided the results below :
U.S.G.S. No. 30 — Alliance mine. From stope on 70-foot level
Collected by Page, .5/1/42. About 100 lbs. of light-colored ore
CaO, 0.13% ; Fe 2 O a , 0.80%. Color fired 2,300° F, light cream
some specks. 2% impurities.
The dark talc probably has not been used for radk
electric purposes. It is said to be relatively high ir
alumina, and may therefore contain pyrophyllite or chlor-
ite. The Bureau of Mines supplied the laboratory result*
shown below, but evidently made no test for alumina.
U.S.G.S. No. 68 — Alliance mine. Collected by Wright anc
Page from ore pile ; about 20 lbs. CaO, 0.16% ; Fe 2 O a , 0.74% ,
Color fired 2,300° F, light cream. Mineral impurities, verj :
low ; abrasion, soft.
These interesting results show that the calcium and
iron content of the dark talc is essentially the same as
that of the light-colored talc, and that this dark ore burns
light. The dark talc may be steatite even though it is nol
marketed as such.
The Alliance ore is more chunky and less brittle thar,
that of the other nearby mines, and would appear to be
more suitable for lava-grade block talc. The Geologi
cal Survey submitted block specimens to M. Kirchbergei
& Co., Inc., for machining and firing tests. The Survey's
samples and Kirchberger's results are shown in Table 2
Irish Lease
This property, immediately adjacent to the Alliance
mine, is owned (as of 1942) by Mrs. Eva Irish, 929 Soutl
Detroit Street, Los Angeles, California. When visited bj
the writer it was operated by a lessee, W. J. Quacken
bush of Darwin, California.
Development at the claims has all been recent, appar
ently, and on a very small scale ; the entire productior
has amounted to only a few hundred tons. As showr
in plate 4, there are four shafts, three of which are
scarcely more than deep pits (8 feet, 17 feet, and IS
feet deep, respectively). The fourth shaft, very close tc
the others, was more than 35 feet deep in May 1942, and
was connected with short drifts which are shown ir
part in figure 15.
Occurrence and Nature of the Ore. All workings lie
along or near the contact between silica rock and slate
(pi. 4, fig. 15), where a zone of alteration includes dis-
continuous masses of talc. The slate dips at an angle ol
50°-60° into the silica rock with a discordance of aboul
20° between the two, and it is likely that a fault existed
here prior to the formation of the talc.
The talc, more or less enveloped in partly softened
rock, occurs in irregular streaks, blebs, and masses thai
are generally distributed in an elongated zone, but whicl
individually are not all parallel with the zone. The talc
bearing ground is at least 35 by 250 feet in plan, but onh
a small portion is actually talc. Most or all of the tal<
originated from the alteration of silica rock.
The ore is fine-grained, soft, and blocky ; it is more
opaque and more nearly pure white than the Alliance
product. The Bureau of Mines has kindly made an analysis
which is as follows :
U.S.G.S. No. 67— Irish lease. Collected by B. M. Page fron
loading chute (weight about 20 lbs.). CaO, 0.16%; FeO
1.16% color fired 2,300° F, buff; mineral impurities, verji
low, abrasion, soft.
Talc Deposits op Steatite Grade, Inyo County
Table 2
Weigh t
in pounds
No. Where collected
AIM Sierra Talc Co. mill at Keeler 3£
All-2 Sierra Talc Co. mill at Keeler 9i
All-3 100-level 4|
All-4 Carlson raise in mine 7|
Original
color
Mottled gray
Black
Dark gray
Dark gray
Fit ittti
text*
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Iron
ii.ntli
Low
Low
Low
Medium
Machine-
ability
G I
Good
( rOOd
Good
23
Conclusion
Best *
Fair
Good
Xo value
* This sample was the best of 22 samples tested from steatite-producing mines.
Thus the ore appears to be well within steatite limits
in all characteristics for which it was tested. The actual
use of the talc, however, is unknown to the writer.
NW
8
SE
M
ot tolc olong-^V
drifl pmche
plone of' sei
E XPLANATION
£31
Tolc-oDserved
Tolc-probable
Altered silica rock
Contoct t Dashed where
approximately located)
Figure 15. Cross-section
B-B' of the
California.
Irish lease, Inyo County,
White Mountain Talc Mine 23
The White Mountain mine was studied by L. A.
Wright and B. M. Page during 5 weeks in August and
September 1942.
The mine is within and adjacent to an unnamed can-
yon on the east side of the Inyo Range, Inyo County,
California (fig. 3). It is reached by road via Lone Pine
and Keeler, the latter village being only 8 or 9 miles away
by direct line, but 35 or 40 miles by road. More than half
the road is unpaved and a part is very steep. The altitude
of the area (between 6,000 and 7,000 feet) is such that
surface operations are hampered by snow in the winter.
Above the mine are spectacular limestone cliffs near the
crest of the Inyo Range (fig. 16). The area is in the belt
of juniper and pinon, which were formerly used for tim-
bering the mine workings. The White Mountain mine has
a scanty water supply, which is piped a mile or two from
a high spring above the camp.
13 This section has been compiled from a report by Lauren A.
Wright and Ben M. Page.
It is said that the White Mountain talc was known
to Indians and that some was sold by them to the old
and famous Cerro Gordo mine for use as a refractory.
In 1914 Roy C. Troeger of Los Angeles, California,
claimed the deposit, which was named the Cerro Gordo
Xoapstone. Mr. Troeger was still the owner of the mine
in 1942, but had never operated it. It was virtually unde-
veloped until some time in the 1930 's when it was leased
by the Sierra Talc Company, which came into ownership
of the Florence and Mae West properties nearby. Mining
of the White Mountain talc was found to be unprofitable
to the company, so the lease was given up after about
5 years. Ownership of the Florence and Mae West was
retained, but no subsequent work on those two properties
has been done directly by the company.
William Bonham of Line Pine succeeded the Sierra
Talc Company as operator of the White Mountain mine,
which he has leased since 1938 from Roy Troeger. Under
this arrangement the mine has become one of the few pro-
ducers of steatite in the United States.
Brief notes concerning the White Mountain mine
have been published by Tucker and Sampson. 24
Mine Workings and Operation. There is no inte-
grated system of workings at the White Mountain mine ;
instead about 40 adits, many of which were begun for
prospecting purposes, are scattered over an area of 30
acres. Most of the adits show at least traces of talc, but
few have exposed minable bodies. The one place where
interconnected workings once existed is in the central part
of the mine, where the Sierra Talc Company drove a tun-
nel and worked one or two additional levels. The portals
of this tunnel are labeled 8 and 16 on the accompanying
map, plate 6. (AH such numbers are arbitrary designa-
tions by the writer.)
The Sierra Talc Company mined from the glory hole
above the aforementioned tunnel, and from a small glory
hole near adit no. 2. Most of their production came from
the larger glory hole. The company also drove part of
adit no. 36 and sank a 30-foot shaft, now caved and obliter-
ated, near adit no. 24. As they were unable to apply large-
scale methods of mining, the company abandoned the
operation. Nearly all of the subsequent workings have
been made by William Bonham.
Mr. Bonham discovered a steatite ore body just be-
neath the ground surface and just above the old tunnel
driven by his predecessors. The removal of this ore left
"the Big Room" (see pi. 6). Since the exploitation of
"the Big Room," mining and prospecting have some-
times consisted of "gophering" by a crew of four to eight
men. Hand drilling is preferred, most of the rock being
soft or well fractured. When ore is found it is usually
-'♦Tucker, W. B., and Sampson, R. J., California Div. Mines Kept.
34, pp. 492-495,' 1938.
24
Special Report 8
taken out by wheelbarrow or by mine cars and dumped
directly into a truck, which takes it about 40 miles to
the Sierra Talc Company's mill at Keeler. Selective blast-
ing and shoveling are employed, but no hand sorting
is done.
During the time of the writer's investigation a small
amount of ore was mined from adits numbered 11, 28, and
2!) on plate 6. No ore was blocked out ahead of mining.
Production. The Sierra Talc Company produced
less than 100 tons a month from the White Mountain mine
and probably reached a total of 2,000 to 5,000 tons. Under
the present system, about 200 tons a month is being
shipped and it is thought that Mr. Bonham has produced
altogether 3,000 to 6,000 tons. This would make the out-
put of the White Mountain mine between 4,000 and 10,000
tons, during a period of approximately 10 years up to
the end of 1942.
Despite the difficulties of its operation, the mine was
one of the two producers of steatite in the United States
at the opening of World War II, and it still holds an
important place in the industry. By agreement, the Sierra
Talc Company has the exclusive privilege of buying the
talc.
Rock Units. The rocks at the White Mountain mine
represent a thick sedimentary section that has been faulted
and subjected to igneous intrusion and hydrothermal
alteration. Certain stratigraphic relationships are there-
fore indistinct. The sedimentary rocks contain no recog-
nizable fossils, but a Paleozoic age is assumed from the
presence of crinoids, corals, and brachiopods in nearby
formations of similar lithology. Alteration near the talc-
bearing zone has locally converted some rock varieties to
white, pulverent materials, and in some cases the original
rock cannot be determined.
Figckb Hi. Part of the White Mountain mine. Camera facing- south-
west. Photo l/.i/ L. A. Wriylit.
1 ) Banded Limestone. A white and light gray-
banded and stratified limestone that occurs in isolated
masses within a massive dolomite is assumed to be the
oldest of the rocks near the mines. It is exposed in the
southwest corner of the White Mountain area, is separated
from the other sedimentary units by a fault, and bears no
relation to the talc bodies. It is the only non-inagnesian
limestone in the vicinity and undoubtedly represents tht
relatively unaltered portions of a rock now largely dolo
mitized. Local distortions occur within the limestone, bui
cannot be recognized in the surrounding dolomite.
2) Flinty Dolomitic Limestone. A gray to black
fine-grained flinty dolomitic limestone is the oldest rock
east of the above-mentioned fault, within the mine area.
The flint occurs in varying abundance as thin, discontinu-
ous, irregular layers which are generally the main indica-
tions of bedding. The upper portion of the limestone is in
places characterized by well-defined bedding planes and
by the absence of flint. This is shown in the workings of,
the White Mountain mine north of the main canyon.
Hydrothermal processes related to or contempora-
neous with those producing the talc have altered parts of
the flinty dolomitic limestone in the immediate neighbor-
hood of the ore bodies. The two most common products of
this wall-rock alteration are: (1) a gray, soft, micaceous
rock superficially resembling shale, and (2) white, fibrous
aggregates of tremolite and other silicates. Flint, where
present, has remained unchanged in both types of altera-
tion.
3) Sandy Dolomite. A gray sandy dolomite that
weathers to a buff color occurs stratigraphically higher
than the flinty dolomitic limestone at the White Mountain
mine. An uncomformable relationship is possibly indi-
cated by a locally exposed angular discordance and angu-
lar flinty dolomitic limestone blocks within the sandy
dolomite at one place. The sand occurs as well-rounded
grains in layers which are in places cross-bedded. These
layers, although difficult to recognize on fresh surfaces,
are brought into prominent relief by weathering.
4) Silica Rock. A white to light-gray, massive silica
rock occurs at several horizons in and above the upper
portion of the flinty dolomitic limestone, and commonly
separates the limestone from the overlying rocks. The
silica rock is composed essentially of quartz, is generally
associated with the most highly altered rocks, and is found
near most of the talc occurrences at the White Mountain
mine. These relations, together with its discontinuous
distribution, would seemingly indicate a hydrothermal
origin. The same inference may be drawn from the "jig-
saw" texture of some specimens (fig. 17). However, a
sedimentary origin is suggested by possible bedding
planes, and by the rounded grains of quartz in some speci-
mens.
5) Massive Dolomite. A massive, coarsely crystal-
line, white, light-buff or gray dolomite occurs at the White
Mountain mine ; it is coarser and somewhat paler than
that at Talc City. All such dolomite has been mapped as
a single unit although probably several sedimentary rock
types have been dolomitized. (Iradational contacts exist
between the massive dolomite and both the sandy dolomite
and banded limestone.
A large portion of White Mountain talc occurs in a
zone near the contact of the massive dolomite with the ;
adjacent rocks.
6) Dikes and Sills. Igneous rocks composing dikes
and sills appear to be of two or more kinds. The central
dike (pi. 6) is an intensely altered rhyolite or andesite
with remnants of hornblende needles, vague outlines of
feldspar phenocrysts, and specks of pyrite and limonite.
Talc Deposits of Steatite Grade, Inyo County
■>:.
Pine chlorite occurs fairly abundantly in the dike. The
rock is »Tay at depth, but near the surface the character-
istic color is rusty and mottled.
Some of the sills in the area are probably basic ande-
site in composition, consisting 1 of plentiful altered feld-
spar phenocrysts and indeterminate groundmass minerals,
with pyroxene converted to chlorite. These sills are green-
ish in color.
7) Mantle. A mantle covers large portions of the
area. In some places it is simply thick soil, in others it is
landslide, mudflow, or ta'us material. It consists in some
places of a single rock type, most commonly massive dolo-
mite or silica rock, large boulders of which often appear
to be nearly in place. In such places, however, the under-
lying rock is not invariably the same type as that which
predominates in the mantle.
The mantle has an observed maximum thickness of
15 feet where it is cut by the mine workings, but it is
probably thicker elsewhere. Talc deposits, undiscovered
as yet, may be complete'y covered by the mantle.
Geologic Structure. Most of the structural fea-
tures are shown on the map (pi. 6) and on the geologic
cross sections (pi. 7).
The White Mountain mine lies within a zone of north-
west-trending faults which vary in size and continuity.
These faults have, as associated structures, innumerable
small, discontinuous shears with non-uniform and very
diverse attitudes. Folding is secondary in importance and
is partly the result of drag along the larger fault planes.
Several of the faults are of sufficient size to be recognized
on the surface although their traces are partly obscured
by alluvium and mantle. The three most important of
these have been designated as (1) the western fault, (2)
the eastern fault, and (3) the central fault zone.
The western fault, which is the largest and appar-
ently the most structurally significant of the three, tra-
verses the southwest corner of the area and can be traced
to the northwest for more than a mile. Future mapping
may show that it is a Bas!n and Range type of fault. It
is characterized by a zone of dolomitic breccia and elon-
gated dolomite blocks; this zone, within the area, averages
80 feet in thickness and separates massive dolomite with
its associated banded limestone on the southwest from
similar dolomite and talcose silica rock on the northeast.
The fault has a nearly vertical dip where it is exposed
underground. The talc bodies are limited to the area
northeast of the fault and similarly the banded limestone
occurs only to the southwest of the breccia zone. Post-talc
movement truncating the ore-bearing zone is inferred, as
no hydrothermal effects are localized along the fault.
The eastern fault, which also probably is of regional
importance, crosses the northeast corner of the area.
Mantle, however, covers a portion of its northwest exten-
sion. Where best exposed south of the main canyon, the
eastern fault is a brecciated zone averaging 20 feet in
width. It is bordered on the northeast by massive dolo-
mite and on the southwest by flinty dolomitic limestone.
The fault dips gently westward in exposures near the
main canyon, and steepens southeast of the canyon. A
small andesite dike closely parallels the trace of the fault
for a distance north of the canyon, and suggests the
presence of an ancestral fault prior to the igneous intru-
sion. No talc bodies have been localized along the fault.
however, and it is probable that its more recent move-
ment occurred after the emplacement of talc.
The central fault zone, which is partly occupied by
a dike, traverses the central portion of the area. It inter-
sects two of the main talcose areas and in places contains
talc. Recurrent movement has sheared and intimately
fractured the dike, and has apparently caused masses to
be separated from the main body. Underground exposures
indicate a great local variance in the direction of strike
and degree of dip of the dike and associated faults. Drag
along the northeastern boundary of the dike has com-
monly produced parallel anticlinal folding in the flinty
dolomitic limestone and indicates a relative upward move-
ment of the rock on the northeast side.
One fault of the central zone is known to the miners
as the "Black Wall" (see section B-B', pi. 7). It closely
parallels the southwestern border of the dike in the vicin-
ity of the glory hole. It is locally well exposed both on
the surface and underground but cannot be extended with
certainty for a great distance in either direction. Wher-
ever recognized, the "Black Wall" consists of a zone of
gouge and breccia of varying width, separating black
flinty dolomitic limestone from light-colored silica rock.
Talc occurs not only as crushed material within the
faulted zone but also as discontinuous bodies within each
wall rock. The fault changes in attitude from a northwest
strike and a vertical dip in its southernmost exposure to
an east strike and a gentle southward dip where last seen
to the west.
Whether the "Black Wall" fault existed as a struc-
tural feature which localized the talc, or whether it de-
veloped because a talcose contact zone offered the easiest
relief to stresses is not certain. Obviously some movement
has taken place since the formation of the talc. If the
fault antedates the talc, the "Black Wall" may be ex-
pected to extend southeastward with a reasonable degree
of persistence beneath the mantle and at the same time
retain its talcose nature. If the fault is younger than the
talc, however, it would probably change its direction of
strike to conform with the talcose border of the silica
rock, or would distribute itself into a number of small
barren shears.
Figure 17. Photomicrograph of silica rock. White Mountain
mine. The principal mineral is quartz, in interlocking urain-. show -
ins incipient rims of talc. Crossed nlcols.
26
Special Report 8
The Talc. The White Mountain talc occurs as sev-
eral varieties, which may be grouped into three main
categories according to color as follows: (1) light-colored
talc, (2) moderately dark talc, and (8) "black" talc.
(1) The light-colored talc is white to gray white to
tan, the last tint being common near the surface of the
ground. Most of the light-colored talc is fine-grained, and
except where sheared it lacks foliated or platy structure
and breaks into irregular lumps. In places the texture is
coarse enough to impart a very fine sugary appearance.
The light-colored talc is softer than the fingernail but
harder than some other talcs, and is less brittle than the
Talc City material, which it approaches chemically. An
analysis furnished by the Sierra Talc Company is as
follows :
Percent
SiO. 01.40
A1»0 : , 1.57
VvA), .!M)
CaO .40
Percent
MgO 31.21
Xa,<) and K 2 .19
Loss on ignition 5.09
100.76
Iron Machine- Con-
oxide ability elusion
Good No value
This composition, together with other favorable charac-
teristics, places the tale among the best grades of steatite.
This high-grade talc is derived not from the dolomite,
but from silica rock. This is graphically indicated in
figures 17 and 18, which illustrate the steatization of silica
rock. Because of this origin, the main impurity found in
the talc is quartz, rather than carbonates or tremolite
which occur in many types of talc.
The chunky and relatively tough nature of certain
varieties of the ore, together with the favorable composi-
tion, make some of it suitable for lava-grade block talc.
The Geological Survey submitted block samples to M.
Kirchberger & Co., Inc., for testing. The results are as
follows :
Where Wt. in
No. collected lbs. Firing test
WM-1 Mill at
Keeler 4J Satisfactory High
WM-2 Mill at
Keeler — 4J Unsatisfactory Medium Good No value
WM-3 Mill at
Keeler 17i Satisfactory Medium Good Good
WM-4 Mill at
Keeler — 5 Satisfactory Medium Good Fair
WM-5 Mill at
Keeler 9 Satisfactory Low Good Good
Although the foregoing data are not all favorable, the
results are better than those obtained from most other
California talc. No megascopic defects were noticed in
the unsatisfactory samples prior to firing, but further
experience might enable one better to evaluate the mate-
rial before actual testing.
(2) The darker talc is a neutral gray, but otherwise
resembles the light-colored talc superficially. When
ground it yields a white powder. This type of talc was
formerly not accepted for radio ceramics, but in 1942
some of it was included in shipments of steatite. A sample
(U.S.6.S. no. 41) was sent to the Bureau of Mines for
analysis and was found to contain only 0.07 percent CaO
and 0.58 percent Fe 2 0a.
('■]) The "black" talc is dark gray, but underground
it appears to be black. When ground it yields a grayish-
white powder. It is more brittle and more thoroughly
fractured than the other two types, commonly occurring
£
¥
0. 5 mm
t
Figure 18. Photomicrograph of silica rock partly altered to talc,
White Mountain mine. The large grains are quartz, with frayed
and embayed edges because of partial replacement by talc, which
is the fine interstitial material. Crossed nicols.
in fragments an inch or two in length. It is always asso-
ciated with dark dolomitic limestone and is believed to
have retained the pigment of the limestone. Very little
importance has been attached to this talc, partly because
it is not abundant, but some has found its way into stea-
tite shipments. A sample (U.S.G.S. no. 40) was sent to
the Bureau of Mines for analysis ; the CaO content was
0.88 percent, and the Fe 2 3 was 1.06 percent, so these
two impurities fall within the range permissible in stea-
tite.
There are also small quantities of decidedly green
"talc" in and along some of the dikes and sills. It prob-
ably consists chiefly of chlorite, but this opinion is based
upon a cursory examination.
All the varieties of talc merge into country rock to
some extent ; for instance, there are all gradations be-
tween silica rock and pure white talc. Some of the inter-
mediate materials ("semi-talc") are difficult to distin-
guish from pure talc. Inclusions of partly altered country
rock are numerous in the ore bodies, and some talcose
fragments or nodules are found to have siliceous or cal-
careous cores. The thorough fracturing of most ore bodies
makes it impossible to sort out all of the talc fragments
from the intermingled impure material.
Localization. The distribution of the talc is graph-
ically shown on the accompanying surface map (pi. 6),
cross sections (pi. 7), and underground maps (pi. 8). It
is obvious that there is no single large ore body, but in-
stead an unknown number of small ones.
The ore controls include: (1) contacts between va-
rious rock types, (2) faults and fractures, and (3) favor-
able rocks, to some extent. The first might be regarded as
a special case of the second, since some movement has
occurred along practically all contacts in the area. In
general, the contacts are more important than shears and
faults within a single formation.
Talc at the White Mountain mine is not restricted to
any particular rock type, but the individual kinds of talc
are thus restricted. Unimportant "green tale" (chlorite?)
occurs in or along dikes and sills, "black" talc is found
Talc Deposits of Steatite Grade, Inyo County
27
in dark dolomitic limestone, and white talc of steatite
jrade is generally associated witli the silica rock or massive
lolomite. For this reason a silica hanging wall is favorable.
There appear to he certain areal restrictions in the
listribution of the talc of this mine. Xo tale was found
west of the western fault or north of the contact where
the massive dolomite begins along the northern edge of
the map area (pi. 6). In fact, only small stringers of tale
iave been found anywhere in the massive dolomite that
partly encircles the productive area, and this dolomite
might be classed as unproductive except for the fact that
a mile away it contains some of the talc bodies at the Flor-
ence mine.
No talc was observed in otherwise unaltered rocks.
There is invariably other evidence of hydrothermal activ-
ity besides the presence of talc. The hard black, unaltered
portions of the flinty dolomitic limestone are barren, but
(this same formation in some places has been altered to
i paler material containing talc. The silica rock also is
•ommonly altered, friable, and pulverent where talc is
'ound.
Principal Ore Zones. The geologic map (pi. 6) shows
hat in the broadest sense there are two talc-bearing areas
it the mine. The first is a lar»e islandlike mass that
>ccupies the center of the terrain shown in plate 6 ; it
•onsists essentially of flinty dolomitic limestone, and it is
/irtually surrounded by massive dolomite. This is the
nain producing area. The second, to the northeast, is a
small counterpart of the first ; it consists of the same flinty
lolomitie limestone, and is partially surrounded by the
aassive dolomite. The following descriptions apply to the
arjier of the two areas.
The ore so far discovered in the main producing area
>ccurs in two <reneral zones. The first, the peripheral zone,
-kirts the outline of the limestone island at or near the
•ontact with the massive dolomite. The second, the central
pone, has not been extensively explored and may be more
ipparent than real. Seemingly it crosses part of the island
liagonally at or near the central fault and dike but only
:he two ends of the central zone have been opened by mine
workings.
The ore bodies of the peripheral zone are flat or
gently dipping, somewhat frajimental masses of talc and
include country rock and semi-talc. The talc body that is
south and west of the glory hole is over 160 feet long, 60
feet wide in horizontal plane, and locally 12 feet thick.
The one that is alongside and west of the "Big Room" is
narrower, but is about 200 feet long. Both of these ore
bodies are associated with contacts between silica rock and
flinty dolomitic limestone or between silica rock and mas-
sive dolomite (see pis. 6, 7 and 8). The other talc bodies
now exposed in the peripheral zone are much smaller
lenses and irregular masses.
The talc of the central zone has favored the margins
)f the central dike and the faults associated with the dike.
One of these faults, the "Black Wall" is a westward-
lipping fracture that in places separates black dolomitic
limestone from white silica rock. The dark dolomitic lime-
stone is partly altered to "black" talc, which has not
been extensively mined. The crushed silica rock has
locally been converted to white talc of steatite grade, rang-
ing from a knife edge to more than 5 feet in thickness (see
pis. 7 and 8). An example of talc localized at the mar»in
of the centra] dike itself is to be seen in adit no. 29, where
1 to 3 feet of moderately light-colored tab- borders the
dike, and where "black" tab- about 1 to li feel thick bor-
ders both the dike and the discontinuous light-colored
talc. A much greater quantity of white talc was found
next to the dike in adit no. 36, probably because crushed
silica rock that was highly susceptible to alteration was
more abundant here.
As might he expected, the largest talc bodies so far
discovered are at or near the juncture of the peripheral
and the central zones. The most extensively mined area
is near the glory hole and "Big Kooni" where the central
dike and the "Black Wall" fault converge, owing to a
difference in dip, and at the same time approach the mas-
sive dolomite contact. The presence of abundant silica
rock makes the situation completely favorable. Extensive
mining and subsequent eaving have made it impossible
to determine the exact size and shape of the talc masses in
this vicinity, and evidently there are no geological records
relating to the old workings.
Most of the above-mentioned geological factors also
apply to the occurrence of tale in adit no. 36. Again there
is the central dike, the borders of which acted as loci of
shearing and hydrothermal replacement, and plentiful
silica rock, and the massive dolomite contact is nearby.
Considerable tale was found here, although not as much
as near the glory hole.
The basal part of the mantle in the vicinity of the
talc ore bodies locally contains abundant tale fragments
that have remained as an insoluble residue where the
dolomite has been removed in solution. The creep of the
mantle has found the least frietional resistance in this
talcose zone and has produced small shear planes in the
mantle parallel with the surface of the ground. At several
localities quantities of tale in the mantle were thought to
indicate the presence of underlying ore deposits. Adits
driven beneath showed the bedrock to be barren. It is
probable, however, that talc bodies yet to be discovered are
completely covered by the mantle.
Florence Mine 25
The Florence mine was studied by L. A. Wright and
B. M. Page during 3 days in September 1942. This prop-
erty is below and to the east of the White Mountain mine,
in the Inyo Range (fijj'. 3). It is in the same canyon as the
White Mountain mine, and is reached by the same road
from Keeler. The Florence talc deposit is about 5,500 feet
above sea level, and is in a pinon-covered terrain without
a water supply. Water is hauled from the White Moun-
tain mine.
The Florence mine is owned by the Sierra Talc Com-
pany of Los Angeles, and is operated for the company
by Mr. William Bonham.
Workings, Operation, and Production. In 1942, de-
velopment consisted of some 40 cuts, adits, and shafts
scattered over an area about 0.6 mile long and 0.1 mile
wide alonjr both sides of a canyon. The accompanying
map, plate 9, shows only the site of recent mining on the
south side of the canyon. This was the only place where
workings extended to any depth, and the only place where
recent stoping had been done. The main adit here is about
80 feet long, reaches a depth of 54 feet, and is in talc
throughout.
25 This section has been compiled from a report by Lauren A.
Wright and Ben M. Page.
28
.Special Keport 8
EXPLANATION
iit*
Talc
Silico rock
NfdlV'A
Flinty, dolomitic limestone
sd
Sandy dolomite
Contact, showing dip
(Dashed where approximately located)
Fault or shear, showing dip
(Dashed where approximately located)
Strike and dip of beds
Ore chute
B. M. Poge and L. A. Wright, 1942
Figure 19. Map and cross-section of the main adit, South Deposit, Florence mine.
At the time of the writer's visit to the mine, the main
adit was not being worked. Since 1942, mining has shifted
to the north side of the canyon beyond the area shown in
plate 9, and talc of better quality has been produced. 20
Some of the older workings, now partly caved and
abandoned, must have furnished at least a few hundred
tons of talc. The mine 's total output is not readily ascer-
tained, but probably during its existence of about 10
years it has produced only 1,000 to 3,000 tons. At the
time of the geological study, production was negligible
because the mining crew was needed at the White Moun-
tain mine. The operation has been sporadic, but at times
has yielded 50 tons or more of talc a week.
Although attempts have been made to hand sort the
ore, this is only partly successful because the material
falls to pieces during mining and is therefore too fine to
be sorted.
The Sierra Talc Company, owner of the mine, mills
the talc at Keeler and sells it for non-steatite purposes.
General Geology. The rocks at the Florence mine
are similar to those of the White Mountain mine, and
may in part be identical.
The most striking geological features are long east-
west slivers of dark dolomitic limestone, locally flinty.
They are embedded in an immense area of massive dolo-
mite that is partly a coarse marble. At least a part of the
massive dolomite originated as an alteration of the darker
stratified rock, but in many places the two types are now
separated by faults.
20 Booth. Otis, oral communication.
rather thick
may contain
As at the White Mountain mine, a
mantle covers some of the terrain, which
undiscovered talc deposits.
The South Deposit. The southern Florence work-
ings (pi. 9) are in the largest sliver of flinty dolomitic
limestone. This sliver is 250 feet wide in one place, but in
a distance of 1,000 feet along the strike it dwindles to 8
feet in width. Its total length is well over 1,600 feet and
may be more than a mile. This elongated sliver is locally
or perhaps entirely separated from adjacent massive
dolomite by southward-dipping faults.
Some of the talc occurs in small quantities adjacent
to a mass of silica rock and some is scattered within white,
altered, powdery parts of the flinty dolomitic limestone.
The bulk of the talc, however, composes a tabular body
along a steep south-dipping fault (see fig. 19). This fault,
where exposed in the main adit, lies well within the flinty
dolomitic limestone sliver; but farther west it seemingly
coincides with one edge of the sliver, which is bordered
by massive dolomite.
The south deposit where best exposed is from 1 to 2
feet thick. In places it is bounded by distinct walls, but
elsewhere there are false walls, and the true thickness has
not everywhere been determined. The measurable length
of the talc body is 105 feet, but talcose material occurs dis-
continuously for 900 feet along the strike. The western-
most showing of talc is about 450 feet beyond the map
area of figure 6. It is not known how much, if any, of the
talc in this deposit is steatite; much of it definitely con-
tains too much lime.
Talc Deposits of Steatite Grade, Inyo County
29
Other Talc Deposits. Several talc deposits at the
Florence mine occur beyond the area shown in plate 9,
and were* not mapped by the writer.
On the north side of the canyon, directly across from
the south deposit, a new prospect was being opened up in
1942. A 4-foot thickness of light-gray talc was exposed
here in a 12-foot adit. The talc is at or near the contact
between light-colored massive dolomite and an included
sliver of dark-gray dolomitic limestone. Talc showings
appear discontinuously on the surface for a distance of
180 feet to the west.
Farther west a similar occurrence of talc is exposed
at intervals for a distance of 75 feet. There is only one
small excavation here.
Still farther west, well up on the north side of the
canyon, is an altered zone in massive dolomite. This
altered zone is 5 to 30 feet thick, about 200 feet long, and
contains streaks and lumps of talc that comprise 20 per-
cent to 50 percent of the zone. An abandoned open cut
35 by 20 feet and several other workings are in this zone.
A more extensively mined deposit is near the western
border of the Florence area. Caved adits, now wholly in-
accessible, have apparently penetrated a sliver of dark
flinty (?) dolomitic limestone, surrounded by light-col-
ored massive dolomite which contains some silica rock.
Near the caved portal of the workings a 6-foot thickness
of moderately dark talc occurs between a hanging wall
of silica rock and a footwall of dark dolomitic limestone.
Nearby the latter rock contains an altered zone 6 to 10
feet thick, of which about 20 percent is talc. Perhaps the
workings that are now caved explored still other talc
deposits.
Below some of the deposits described above, near the
level of the road up the canyon, is a discontinuous bleached
zone nearly 500 feet long. Much of the zone is only 1 foot
thick, but it ranges to 10 feet thick. In places it contains
streaks of talc aggregating from ^ foot to 3 feet in thick-
nesses, but in other places it is barren. This bleached
zone is locally near the edge of a silica mass, but elsewhere
occurs near the contact between pale massive dolomite
and a sliver of dark flinty dolomitic limestone. It is pene-
trated by 8 abandoned small cuts.
In several places small veinlike streaks of talc were
noticed in shears and joints within the massive dolomite,
in some cases branching complexly. These small veins are
not workable.
The Talc. The talc at the Florence mine ranges in
color from medium gray or tan to gray white or greenish
white. The latter is the most prevalent tint in the talc of
the south deposit shown in plate 9.
The talc is universally fine-grained and lacking in
true foliation or fibrous character. For the most part it
has been crushed and sheared to a marked decree and
therefore occurs chiefly in a fragmental state. The frag-
ments of talc in the south deposit are partly separated
from one another by thin calcite films, which may have
been deposited by surface waters. Other megascopic impur-
ities include scattered small calcite crystals and, less
commonly, specks of pyrite and limonite.
The Geological Survey submitted over 100 pounds of
talc from the south deposit to the Bureau of Mines for
jtesting. The sample (II.S.G.S. no. 39) showed 3.44 per-
cent CaO and 0.86 percent Fe_>0 :! , and therefore cannot
be considered steatite and is not sold as such. However,
this single analysis does not condemn the whole deposit,
which has not been systematically tested.
Some of the talc from deposits on the north side of
the canyon is said to be of higher quality, the CaO con-
tent ranging from 1.26 percent to 3.0 percent. 27 The
Sierra Talc Company has kindly provided an analysis of
such material, which shows only 1.14 percent CaO, 1.26
percent Fe ? 3 , and 1.72 percent A],() :i . Therefore, some
of the talc is presumably of steatite grade. However, it is
used in cosmetics and nonradioelectric ceramics.
Trinity Talc Mine
The Trinity mine is between Keeler and Darwin,
about 1 mile southwest of the Talc City mine. In the past
it has been known as the Pacific Coast Talc mine 28 and
as the Angelus Talcs. Formerly owned by the Pacific Coast
Talc Company, it has been acquired by the Sierra Talc
Company of Los Angeles. During the last decade or two
it was a major producer. The following data were ob-
tained by the writer during a cursory examination May
1, 1942, at which time the mine was idle although still
partly equipped.
The geological setting is similar to that of the Talc
City mine. All the talc observed is in the massive dolo-
mite that extends uninterrupted to Talc City, and as at the
Talc City mine, there is at least one mass of silica rock
within the dolomite area. Perhaps the silica rock is the
"igneous intrusive" mentioned by Tucker and Samp-
son. 29 The talc observed at the Trinity does not occur
along contacts, however ; it apparently was formed by the
alteration of massive dolomite only. The ore bodies are
lenses that lie in several attitudes, and which were prob-
ably localized by minor fractures. One lens must have
been at least 40 feet long and 25 feet thick, judging by
the size of the main excavation. The talc seems physically
identical with that of Talc City, being pale green, fine-
grained, and rather massive. It is believed to have about
the same composition, and officials of the Sierra Talc
Company affirm that it is of steatite grade.
The workings consist of several adits, a glory hole, a
gently inclined shaft perhaps 100 feet long, a vertical
shaft more than 50 feet deep, and several drifts, cross-
cuts, and stopes.
Only small remnants of talc are now visible. Un-
doubtedly undiscovered ore bodies exist, but their dis-
closure is not likely without the drilling of prospect holes.
An area that might be explored is just south of the in-
clined shaft at the dolomite-silica rock contact.
A more careful study of the Trinity mine should be
undertaken to determine its potentialities.
East End Mine and Bob Cat Claims
The East End mine is an inactive and largely worked-
out property less than a mile northeast of the Talc City
mine, about 6 miles northwest of Darwin. The East End
deposit is reached by a road from the Lone Pine-Death
Valley highway, and was examined by Lauren A. Wright
and the writer December 8, 1942. It was operated by the
Sierra Talc Company some years ago, and called by them
the East End. It has subsequently been relocated as part
of the Bob Cat claims by R. II. Bagley.
27 Mulrvan, Henry, oral communication.
•"Tucker, W. B., and Sampson, R. J., California Dlv. Mines
Rept. 34, pp. 492-495, 1938.
28 Op. cit., p. 493.
30
Special Report 8
The main deposit contains pale-green, crudely foli-
ated, fine-grained tale. It occurs as a lens between massive
dolomite and a pray, platy limestone from which the dolo-
mite was derived. This lens, largely mined out, is pene-
trated by a 60-foot inclined shaft with an adit meeting
the shaft at the 30-foot level. Between this adit level and
a drift at the bottom of the shaft, the talc has been stoped
for a lateral distance of more than 100 feet, the stopes
being 5 to 15 feet wide. Most remnants of talc around the
margins of the stopes are very thin, from a fraction of an
inch to 2 feet in thickness. Prom the 60-foot level an
inclined winze 35 feet loop follows the same ore body,
which is \ foot to 5 feet thick. At the bottom of the winze
a 70-foot drift blocks out part of the body below the 60-
foot level, but in this drift the tale is thin and pinches to
1 foot at both ends of the drift.
Within 100 feet of the main deposit, to the west and
southwest, a cut reveals a talcose zone in a residual patch
of stratified dolomite and limestone that is surrounded
by massive dolomite. This talc, which is not an extension
of the main body, is mainly very dark and hopelessly
intercalated with country rock. Nearby, a 20-foot shaft
exposes discontinuous talc 1 foot to 4 feet thick.
On the other side of the main deposit, 100 to 200 feet
to the northeast, there are two pits about 70 feet apart.
One pit shows 6 feet of probable steatite and the other
shows 4 feet of similar talc, but nearly continuous expo-
sures of dolomite lie between the two pits. Thus, it is
unlikely that a large talc body extends from one pit to the
other.
Still farther north of the main East End workings,
the Bob Cat claims include a 20-foot shaft and two pits
in separate ( ?) talc bodies 1 foot to 5 feet thick, in mas-
sive dolomite with remnants of original stratified sedi-
ments.
No samples were taken, but the proximity of the Talc
City mine together with superficial resemblance of the
ore and identical occurrence suggest that the talc is of
steatite grade.
Frisco Talc Mine
The Frisco mine was examined by Lauren A. Wright
and the author. The geology was mapped mainly by
Wright during two days in December 1942. The property
is not more than a mile southwest of the Talc City mine ;
it is 6 miles northwest of Darwin, and may be reached by
good roads from Darwin or from Lone Pine and Keeler.
On the Frisco no. 2 claim, a 65-foot shaft and short
drift were made in 1942 by the Sierra Talc Company of
Los Angeles. The shaft is between two sets of old pros-
pects and workings made by the same company some years
ago, but the old developments will not be fully treated in
this report. The old operations produced "green talc"
(chlorite, apparently) said to contain more than 20 per-
cent alumina. After a number of years of inactivity, ex-
ploration was resumed in 1942, and the recent shaft
revealed talc of steatite grade. In July 1942, 100 tons of
steatite was shipped from the Frisco. The next month only
22 tons was produced, and altogether the small mine had
not yielded more than 300 tons of steatite by the end of
1942.
The rocks are identical with those of the Talc City
mine. Their distribution is shown in plate 10.
Limestone, well stratified, appears in two neighbor-
ing, strangely shaped patches. The limestone dips steeply
westward, and the grayish strata project somewhat above
the ground like thick shingles on n\^'.
Massive dolomite is the most prevalent rock.. Its rela-
tionship to the stratified limestone shows clearly that it
has been altered from the limestone by hydrothermal solu-
tions. The dolomite is pale gray to nearly black, free of
fossils and stratification, and forms numerous rough-
surfaced outcrops.
Dikes of pale felsite (rhyolite?) are found near the
mine. One dike is just west of the shaft, and others lie to
the east beyond the map area. Being hydrothermallv
altered, the felsite does not crop out well. Much of it has
been altered to chlorite ( ?).
Silica rock which resembles quartzite (fig. 7) occurs
underground in the shaft and drift made in 1942. The
steatite talc is associated with this silica rock and has been
derived from it.
The main masses of limestone, the felsite dike, and
the strip of silica rock all converge toward a common
point east of the 1942 shaft.
As shown in pi. 10, the talc is near a felsite dike and
close to the edge of the limestone area, but shows greatest
affinity for the dolomite and a steeply dipping strip of
silica rock.
The talc body appears to be somewhat lenticular in
shape. In the shaft it is interrupted by numerous in-
clusions of siliceous rock, and it is probably likewise
interrupted along the strike. The ore is pale, blocky, fine-
grained, and soft. It is of steatite quality, as shown by its
acceptance by the steatite industry. The talc extends down
the shaft 50 feet, but further downward prolongation is
rather doubtful (pi. 10). Lateral development may be
encouraging, however, and if so, the downward explora-
tion may be resumed later. On the surface, intermittent
talc showings extend more than 100 feet along the strike
and the width of the ore body is about 10 feet.
Massive green chlorite (?) occurs abundantly as a
replacement of parts of the felsite dikes at the Frisco
mine. The chlorite (?), which was once produced as
"green talc," was not being mined in 1942. About 1946
the mining of the green material was resumed, and the
mineral is now sold under the name "Sierralite" for use
in cordierite ceramic bodies. It is said to have the follow-
ing composition 30 :
Percent Percent
SiO. 36.24 CaO 1.47
Fe,.0 3 1.19 Ign. loss (HaO)_ 12.19
ALO3 23.56 CO, 0.S6
MgO 23.39 Moisture 0.18
Alkalis 0.35
99.43
Victory Talc Mine
The small Victory mine was examined by Lauren A.
Wright and the author in December 1942, when mine de-
velopment was in progress. The property is 7i miles north-
west of Darwin and 15 miles southeast of Keeler, from
which it is reached by dirt road. The owners are Mrs.
Edith Lockhart and George Koest of Darwin, California,
but the lessees and operators are A. C. Palmer and Ray-
mond Palmer of Lone Pine. Two men were working on
the premises in December 1942.
3,1 Analysis kindly furnished by Mr. Henry Mulryan.
Talc Deposits of Steatite Grade, Inyo County
31
The talc is only 3 to 5 feet wide on the surface of the
<rround, and barren trenches across its projected path limit
the length on the surface of the "round to 50 feet along the
strike. The country rock is gray massive dolomite of the
type found at the Talc City mine a mile away. There is no
visible structural control of the ore.
The talc crops out on a hillside, and the ore was fol-
lowed downward by a shaft about 25 feet deep. A 170-foot
adit driven about 50 feet lower than the shaft collar had
failed to intersect ore in 1942, although it seemingly
passed under the shaft. It was later learned that a raise
reached the talc 12 or 18 feet below the bottom of the shaft.
The quality of the talc is probably good, judging from the
resemblance to nearby steatite deposits.
100-ft
(Y\ drift
EXPLANATION
mm
Talc
Silica rocK
dol
Dolomite
Contact ( Dashed where
approximately located)
Fault or shear
10 5
i
10
Feet
B.M.Page 1942
Figure 20. Cro.sx-section, Viking talc mine.
Viking Talc M ine
The small Viking talc mine is 16 miles southeast of
Keeler and 10 miles northwest of Darwin, and just north
of the highway to Death Valley. The owner is Mrs. Edith
Lockhart of Darwin, who had leased the property to Mr.
Wilcox in April 1942. At that time one man was employed,
and no ore was being produced.
There is a 20-foot shaft on the premises with two
drifts at the bottom, one extending 20 feet and the other
about 100 feet eastward. These workings arc partly in talc
and partly in country rock. On the surface SO feet east of
the shaft there are a 30-fool trench and a short adit that
exposes 1 foot to ."> feet of tale; 15 feet farther east, a pit
exposes 2 to 3 feet of tale in stringers.
The rocks are similar to those at other talc mines in
this region. Light-gray to black massive dolomite pre-
dominates, but within it is an intermittent, apparently
steeply dipping strip of silica rock that resembles .piartz-
ite. The talc occurs sporadically and irregularly along this
siliceous material (see accompanying cross section, fi<>-.
20), and probably was derived from it.
The talc is white, opaque, blocky, and soft. It has some
superficial orange-red stains (which are commonplace in
the district) and a few limonite cubes. No sample was
taken, but nearly all the talc in the district is of steatite
grade except where obvious impurities are too abundant.
White Swan Talc Mine
The White Swan nunc or prospect is perhaps a mile
west of the Viking property and is easily reached by road
from the Lone Pine-Keeler-Death Valley highway. It is
15 miles southeast of Keeler and 11 miles northwest of
Darwin. The writer was there for only a few hours in April
1942. The owner is Mrs. Edna M. Towers, 316 West Im-
perial Highway, Los Angeles. The former lessee was a
Mr. Wilcox, but no one worked the mine during 1942.
Development includes two shafts less than 30 feet
deep, partly in talc, and two or three adits less than 50
feet long in separate talc showings. The main working,
however, is a branching adit shown in figure 21. One
branch is over 400 feet long and mostly barren, while the
other is about 50 feet and was chiefly in ore. The short
branch was expanded into a stope which must have yielded
400 tons of talc. Total production cannot have exceeded
700 tons.
The country rock and ore are superficially identical
with those at Talc City. The country rock is massive gray
dolomite, and the talc is fine-grained, blocky, and pale
green. The ore occurs in frayed lenses and streaks, which
dip steeply. The largest lens (see fig. 21) is visible for 125
feet along the strike but is only 1 foot to 5 feet thick. It
has been mined up and down the dip about 30 to 40 feet.
The continuation of the workable portion may be down-
ward and to the west. The talc has been localized by minor
fractures rather than by contacts between rock types ; it is
chiefly bounded by dolomite, although some silica rock
was noted nearby.
Lakeview Talc Mine
The Lakeview mine is idle, having seemingly been
worked out. It is 2\ miles north-northwest of Keeler, near
the foot of the Inyo Range but about 4,400 feet above sea
level. The loading bin is reached by road from Lone Pine
or Keeler, and the mine itself is 100 yards or so above the
road on a steep hillside.
A. C. Palmer and Raymond Palmer of Lone Pine
were the operators of the property during its chief activ-
ity, and probably produced between 1,000 and 3,000 tons
of talc. The following data were collected by L. A. Wright
and the writer in December 1942.
32
Special Report 8
Talc stope to
i^BQ surface
^ Broken line =
Y ^^\ ^j^level 22 ft above
15- ft/
winze 6- ft
Dolomite
62
Foult or sheor, showing dip
pen cut
S
Head of raise or winze
too Feet
Figure 21. Cross-section, White Swan tale mine.
A vertical shaft 30 to 50 feet deep connects with one
visible level at the bottom. From this level there are two
principal stopes that almost reach the surface. They are
close together, steep, and en echelon ; one is about 25 feet
long and the other is 45 feet. Both stopes are 3 to 10 feet
wide and 2 to 40 feet high. The floors are concealed, but
at one end of the pair of stopes the ore pinches out and
the other end is very near the surface of the ground,
owing to the steepness of the hillside.
One stope is in a steep lens of talc between quartzite
and stratified gray dolomite or limestone. Dark talc
occurs near the latter, and white talc near the quartzite.
The other stope is along a steeply dipping talcose sliver
of dolomite or limestone that is enclosed in a diabase dike.
The diabase itself is not talcose. The ore remnants appear
to be of high quality, and are probably steatite, but they
were not sampled by the Survey.
Blue Stone Talc Mine
The Blue Stone mine is small, inactive, unequipped,
ami perhaps largely worked out, but the remaining talc
is probably of steatite quality. The property is on the
side of a canyon on the west side of the Inyo Range, 10
eel
;he
miles from Independence, and is reached by dirt road via
Mazurka Canyon (see Mt. Whitney quadrangle). The
railroad at Kearsarge is 9 miles away by road.
Walter Sorenson of Lone Pine, California, is the
owner, and W. H. Huntley of Bigpine was a recent lesseel
Mr. Huntley accompanied Lauren A. Wright and th
writer during a 3-hour examination of the mine Nove
ber 30, 1942.
Talc was noticed here by Goodyear 31 in the 1880 's.
The predominant rock is thick-bedded, dark-gray
Devonian (?) limestone containing discontinuous thin
streaks of flint. The strata dip steeply but uniformly
westward. Interbedded with the limestone is a quartzite
member possibly 20 to 60 feet thick, which forms the foot-
wall of the main ore body. The talc occurs within the
limestone, from which it was derived.
The main ore body is nearly mined out, its site being
outlined by a steep lenticular stope that measures about
40 by 40 by 10 feet along its principal axes. The stope,
which yielded the entire 800-ton output of the mine, con-
nects directly with the surface of the ground. From the
lower end of the stope, a chute leads to an adit about 50
feet below. This adit, which was driven in from the moun-
tainside, is 100 to 200 feet long, and although it passes
beneath the ore body and follows the controlling lime-
stone-quartzite contact, it does not intersect any ore. The
downward limit of the stoped body is thus quite definite,
and the longitudinal limits are implied by the fact that
the ore pinches to 12 or 18 inches at each end of the stope.
Other intermittent talc showings 1 foot to 2 feet wide
occur on the surface north of the main deposit, but are
not visibly connected with it. About a third of a mile
south of the main ore body, talc as much as 2 feet in
width is exposed for 50 feet, partly in two small adits.
This talc is bounded by flinty limestone, with no quart-
zite, but is not far off strike from the main body. There
are other small, discontinuous showings of talc.
The ore at the Blue Stone is mainly mottled gray,
soft, blocky, massive talc. The Bureau of Mines kindly
reported as follows on a sample :
I'.S.G.S. Xo. 6") — Blue Stone mine. Collected by Wright and
Page, 11/.SO/4L' (about 15 lbs.). CaO. 0.10%; Fe s 3 , 0.42%;
color fired 2300° F, white; mineral impurities, very low;
abrasion, soft ; Tuscaloosa laboratory rating, O.K.
The material is probably of steatite grade.
Willow Creek Talc Mine
This mine, although small, has reportedly yielded
talc of steatite grade. It is now apparently worked out,
having produced a probable total of about 1,000 tons,
mostly within a year's time. Lauren A. Wright and the
writer gathered the following data during May 1942, near
the termination of mine operations.
The deposit is on the steep south side of the valley of
Willow Creek, which runs through the east flank of the
Inyo Range and empties into the north end of Saline
Valley. The Willow Creek mine is reached from Bigpine
by a poor dirt road, the same one which leads to the White
Eagle mine. The approximate longitude and latitude are:
117° 56' 15" west, and 36° 50' 40" north (see Ballarat
quadrangle). The owner is Emil Carlson of Bigpine, Cali-
fornia. Almost all the development and mining have been
done by a lessee, G. P. Rogers of Bigpine.
3i Goodyear, W. A., California Div. Mines Rept. 8, p. 268, 18S8.
Talc Deposits of Steatite Grade, Txyo County
33
The geology is unusual in that the mine appears to
be in a landslide or an incipient landslide. There are large
topographic benches farther up the mountainside, and the
mine workings are in a highly fractured, extremely un-
table rock mass with many gaping cracks. The most preva-
lent rock is granite. Within it are pendants of white lime-
stone, and along the edge of one pendant a lens of talc
occurs, as shown in the accompanying figure 22, which
indicates the outline of the ore prior to mining. The talc
in us( have been at least 20 feet thick at its widest part, but
it narrows rapidly along the strike. It lies transversely
across a ridge and does not appear at lower levels in the
[ravines on cither side of the ridge.
The outlines of the talc ond
limestone are shown as they
were prior to mining.
Glory hole
\y
ft
r,V4tc
^
yt ..\l^^.~-i^ J ..Cj-n.„ ■ ■■■: ■■v.-:,-.y \ S \ \ '\
vel
NW
EXPLANATION
MsM
Talc
*m
Granite
ssa
Limestone
Contact (dashed where
approximately located)
i i i i i ■ i i i
50
ioo Feet
LA. Wright and B.M Poge,l942
Figure 22. Cross-section, Willow Creek talc mine.
The deposit was mined mainly from two adits which
tapped a glory hole. The ground was initially thoroughly
fractured by natural movement down the steep mountain-
side, and it was further disturbed by the mining. The
lower adit was kept open with great difficulty and consid-
erable danger and expense.
The talc is gray-white, fine-grained, and bloeky, out-
wardly resembling the associated limestone. Officials of
the Sierra Talc Company, which purchased the ore, say
that it is of steatite grade. 32 There is probably additional
talc somewhere on the mountainside above, if the Willow
Creek deposit is actually in a landslide, but unfortunately
the slope is partly covered by other slides.
White Eagle Talc Mine
Geologically, the White Eagle mine is of interest be-
cause much of the talc has been derived from the alteration
of granite. It is doubtful, however, that the talc is of
steatite quality.
At the outset of World War II, the newly developed
White Eagle mine was considered to be a potential source
of steatite. Subsequently, either because of difficulties in
sorting out impurities, or because of variability in the
quality of the deposit, a controversy arose as to the utility
of the talc. A leading radioceramics manufacturer tenta-
tively approved the material, but later condemned a car-
load shipment. Some large samples have given unsatis-
factory analyses, while some small samples appear to be
of steatite quality. If the talc of the White Eagle mine can
be used for steatite, it represents a large reserve.
Lauren A. Wright and the author studied the mine
during May, 1942. The origin of the talc has recently been
discussed by Wright. 33
The White Eagle mine is on the very steep eastern
slope of the Inyo Range overlooking Saline Valley, Inyo
County, Calif., 1 mile south of Willow Creek. The work-
ings are about 3,600 feet in elevation, the ore bin at the
bottom of the aerial tram is approximately 2.500 feet, and
the main camp (near the mouth of Willow Creek) is at
an elevation of around 2,300 feet above sea level. Soil and
vegetation are scanty along the arid eastern side of the
Inyo Range.
The camp is reached by a circuitous route from the
Owens Valley highway. Automobiles must enter Saline
Valley at the north end, following the Bigpine-Waucoba
Canyon road. The road is partly steep, rough, tortuous,
and generally unsatisfactory. Prom the foot of the moun-
tain the mine is accessible only by a trail about half a mile
in length.
History, Operation, and Production. Mr. Elmer
Oaks of Bigpine is the discoverer of the talc deposit. The
property was not exploited until 1941 when it was leased
to Mr. Wright Huntley of Bigpine. The mine was bought
by the Sierra Talc Company in 194.5, but it is still leased
to Mr. Huntley.
Initial development of the property included the
driving of three short adits one of which is in talc through-
out. At the site of the latter adit, an open cut was made.
Talc is mined from this cut, which has been enlarged and
benched. After being hand-sorted, the talc is taken to the
foot of the mountain by means of a 2,000-foot jig-back
aerial tram.
During the first year of production (1941-42) the
mine was inactive a good part of the time. An effort was
being made to produce talc of steatite grade, but sorting
of the ore was difficult and only partly successful. About
1,570 tons of talc was produced in 1941, beginning in
August of that year, but only 700 tons was shipped in the
first 5 months of 1942. Altogether, 2,270 tons had been
3 - Booth, Otis, oral communication.
"Wright, L. A.. White Eagle talc deposit: an example of stea-
tization of granite: (abst) Geol. Soc. America Bull., vol. a9, l>. 138a,
1948.
:u
Sl'KCIAI. lkKl'OKT S
3620
3600 -
3580 -
3560 -
3540 J
•SW
A
+ ^\
^*— + +N—-— Crest of
• -~N + +\ minor ridge
'. + +9' +\y
+ +\
t +\
+ +\
* +\
o es
E XPLANATION
tc
Gro
Bench
Vi-i Do
\ '•■■• \ Foce of cu
\ Tol
V
*° Adit, projected" fc
Tolc
+ r+r +
nite rock with
DUS inclusions
>: . /VV
i dt>l
omitic morble
t
JS
Track yy~~^
1 + X
/ dol^ + + \
i ' i '■ - gr + \ NN £
B M Poge 1942
FEET
line of section
KlIil'KK -
.logii
■tiim Hi main (jujirry, VVhitK ICsigh> mini
produced up to the time of this investigation. The talc is
trucked 187 miles to the Sierra Talc Company mill at
Keelcr.
The Rocks and Geologic Structure. The east slope
of the Inyo Range is an eroded fault scarp, steep and
almost devoid of soil. The rocks near the base of the slope
are sheared and crushed, but the mine itself is farther
removed from the marginal fault which bounds the range,
and considerable continuity was observed in the various
rock units. The steepness of the escarpment has caused
some landsliding, however, even at the site of the talc,
deposit.
The area] geology is shown on the accompanying map,
plate 11.
Silica rock occurs as an elongated body. It probably
is quartzite and displays faint stratification, /unlike the
silica rock of the Talc City mine. Possibly it has been
altered to dolomite in places, as its thickness varies con-
siderably where it is bordered on both sides by dolomitic
marble.
Dolomitic marble is one of the oldest rocks at the
mine. It is light, warm brown on weathered surfaces, but
where freshly broken it is white to gray. Much of the
dolomitic marble is sufficiently coarse that the cleavage
surfaces of the constituent crystals are readily visible at
a casual glance.
Granitic material (probably granite or quartz mon-
zonite) has invaded and partly engulfed the silica rock
and dolomitic marble. The granite is moderately dark
gray, and contains both biotite and hornblende ; the grains
arc small to medium in size. Numerous included slivers
and blocks of dark schists and some basic igneous rocks are
present within the granitic mass.
In general the rock units occur in roughly parallel
bands, as seen in plan, but there is much local irregularity,
the granitic rock is moderately discordant in its relations
with the other rocks. The dolomitic marble appears in iso-
lated patches as well as in continuous bands. The silica
rock varies in width and terminates abruptly at both ends.
The talc body likewise is not tabular nor lenticular in
form. These irregularities in the areal pattern of the rocks
are Ihe result of igneous intrusion and hydrothermal al
tcral ion rather than folding, fault ing, or other mechanics
deformation.
Despite the lack of uniformity in detail, all of tin
mappable units strike nearly north-south, and in genera
diji westward.
Only one fault, a minor one, is shown on the map
However, the footwall of the northern portion of the tak
is a distinct plane which is either a joint or a shear plane
On the whole, joints are notably abundant in this area.
The Talc. Landslide and talus material locally cover
the talc, and prior to the excavation of the open cut, it
appeared that there were two main deposits rather than!
a single large body.
In plan the talc body is "I/' shaped, consisting of
two contiguous segments of unequal thickness that are at
right angles (see pi. 11), and which dip more or less
Inward one another. The lengths of the segments are re-
spectively about 250 and 200 feel. The corresponding map
widths are 88 and !'"> feet, but these figures do not repre-
sent the true thicknesses. Taking into account the dip of
the talc, the slope of the ground surface, and the irregu-
larity of the granite contact, the thickness of one branch
of the talc body is locally 138 feet (fig. 23) and that of
the other branch is locally 4(J feet.
The talc grades into dolomitic marble, granite, and
silica rock, and was almost certainly formed by hydro-
thermal alteration of all three. It contains partly replaced
inclusions of the three rock types. These inclusions are
numerous and are one of the most troublesome features
of the deposit. They range from less than 1 inch to more
than 5 feet in diameter, and commonly resemble rounded
nodules of talc. The talc composing the exterior of the
nodules grades into a core of granitic rock, dolomite, or
silica rock as the case may be, granitic cores probably pre-
dominating. Skill is required in sorting out these inclu-
sions, which are usually not broken open during mining
and which therefore exhibit only the talcose exterior.
Their volume is of some importance but has not been
accurately ascertained. Inspection of the quarry face sug-
gests that they constitute between 5 percent and 20 percent
Figure 24. Photomicrograph of partly talcose granite rock,
White Eagle mine. The rock shown is aboul half feldspar and
half tale. Crossed nicols.
Talc Deposits of Steatite Grade, Inyo County 35
»f the deposit, but the impurities may be even more abun- exposures of country nick definitely limit the ore bodv in
hint in the southern part of the talc body. Thin sections thai direction. The thickness of the deposit, including
>!' partly altered rock show the transition from granitic some "semi-talc", is about 15 feet. The vertical dimension
rock to talc (fig. 24). is still unknown.
The talc is gray white to greenish white and is fine- The country rock is mainly gray dolomite and dolo-
prrained and structureless for the most part. It is soft but mitic marble, stratified in places. Within this material
brittle and is so thoroughly fractured that it breaks into there is a band of silica rock that is either quartzit ■ a
rather small pieces, increasing the difficulty of sorting it hydrothermal product. The talc occurs along the under
by hand. In a few places the talc unmistakably exhibits a side of the siliceous rock, as shown in the accompanying
relict igneous texture inherited from the original granitic sketch, figure 25. The ore is white next to the light silica
rock. rock and dark next to the blue-gray dolomite, l'ossiblv
An analysis kindly provided by the Sierra Talc Com- microscopic graphite was retained during hydrothermal
pany fulfills commonly accepted steatite specifications, as alteration of the dolomite. It is said that the dark color
follows: vanishes during firing. 34
Pe _r™ nt Percent The ore is massive, blocky, soft, semi-opaque, fine-
Si ° a r,!, - 7(! S0:| ° 03 grained, and scarcely stained even at the surface of the
Al*Oa 8.30 Na-O 0.I8 ground. The Bureau of Mines kindly gave the following
Fe^Os 1.10 KaO 0.14 information based upon our two samples :
CaO 0.30 Loss on ignition. 2.38 T.S.C.S. Xo. 63— Eleanor claim. White talc, collected from
MgO 27.81 ndit by Wright and Page, 11/29/42 (about 10 lbs. 1 ; CaO,
T ,. .-, , , , . „ . 0.08%; VeAh, 0.95%; color fired 2,300° F, buff ; mineral
Individual samples such as the foregoing do not rep- impurities, very low; abrasion, soft.
•resent the bulk of the deposit, which is variable. Some U.S.G.S. Xo. 04 — Eleanor claim. Dark talc, collected from
large samples show more than 2 percent FeoO.-j and an • 1,lit hv Wright and Page, 11/29/42 (about 10 lbs.); CaO,
appreciable content of feldspar. ££* ; Fes ° 3 ' 073% ; color Hml 2 ' 300 ° F ' cream; abrasion '
: " Mulryan, Henry, oral communication.
EXPLANATION
tc
White talc
Mottled gray and
blue-block talc
Silica rock
Dolomite
Contoct (Dashed where
approximately located)
Figure 25. Sketch section, Eleanor talc claim.
Eleanor Talc Claim
The recently discovered Eleanor talc claim overlooks
Saline Valley from a point several hundred feet up on the
eastern escarpment of the Inyo Range. It is less than a
mile south of the White Eagle deposit and is approached
by the same road, but the final ascent from the foot of the
mountain is by trail. The approximate longitude and lati-
tude are 117° 55' west and 36° 49' 30" north, juding from
the Ballarat quadrangle map. G. P. Rogers of Bigpine and
Frank Henderson are the owners.
In November 1942, Lauren A. Wright and the writer
gathered the data of this summary. At the time there were
several small cuts and a 30-foot adit.
The orebody is exposed along the surface for about
150 feet (slope distance) . The adit is near the south end of
the deposit. About 100 feet south of the adit continuous
BIBLIOGRAPHY
Anon. (Page, B. M., and Wright, L. A.), Talc in the Ganim mine,
Shasta County, California: U.S. Geol. Survey Strategic Min-
erals Investigation, Prelim. Maps, 194."',.
Anon., Talc: Ceramic Industry, vol. 32, pp. 38-40, 193!).
Dana, E. S., The svstem of mineralogy of James Dwight Dana, 0th
ed., pp. 678-680, 1904.
Diller, J. S., Mineral Resources for 1913, I'.S. Geol. Survey, pp.
153, 155, 157-160, 1914.
Engel, E. A. J., Talc and ground soapstone, in Industrial minerals
and rocks: Am. Inst. Min. Met. Eng., pp. 1018-1041, 1949.
Goodyear, W. A., California Div. Mines Rept. 8, p. 207, 1888.
Klinefelter, T. A., Speil S., and Gottlieb S., Survey of the suitability
of domestic talcs for high-frequency insulators: I'.S. Bur.
Mines Rept. Inv. 3S04, 1945.
Knopf, Adolph, A geologic reconnaissance of the Inyo Range and
the eastern slope of the Sierra Nevada, California, with a sec-
tion by Kirk, Edwin, The stratigraphy of the Inyo Range :
U.S. Geol. Survey Prof. Paper 110, 1918.
Ladoo, R. B., Talc and soapstone: U.S. Bur. Mines Bull. 213, pp.
111-117, 1923.
Sampson, E., Mineral Resources for 1920, Part II. I'.S. deed. Survey,
pp. 203-204, 1923.
Sampson, E., Mineral Resources for 1922, U.S. Geol. Survey, pp.
81-83, 1923.
Tucker, W. B., California Div. Mines Rept. 17, pp. 300-301, 1920-21.
Tucker, W. B., California Div. Mines Rept. 22. pp. 523-524, 1926.
Tucker, W. B., and Sampson, R. J., California Div. Mines Rept. 34,
pp. 492-495, 1938.
Waring, C. A., and Huguenin, E., California Div. Mines Rept. 15,
pp. 126-127, 1919.
Wright, L. A.. White Eagle talc deposit : an example of stent izal inn
of granite: (abst.) Geol. Soc. America Bull., vol. 59, p. 1385,
1948.
Wright, L. A.. California talcs: Min. Eng.. vol. Is7. no. 1. pp.
122-128, 1950; also, Trans. Am. Min. Met. Eng., vol. IK", pp.
122-128, 1950.
42682 4-51 2M
printed m California state printing office
DIVISION OF MINES
OLAF P JENKINS. CHIEF
STATE OF CALIFORNIA
DEPARTMENT OF NATURAL RESOURCES
UNITED STATES DEPARTMENT OF THE INTERIOR
GEOLOGICAL SURVEY
SPECIAL REPORT 6
PLATE I
EXPLANATION
sdl
Stratified dolomite ond
limestone; ton to block
NOTE As nearly as possible, talc bodies ore shown
os they were prior to mining. Most
out at the surface before map was mode
Geology by B. M Page, Morch 1942
Topography by B M Page and M Erickson
SURFACE GEOLOGY OF THE TALC CITY MINE, INYO COUNTY, CALIFORNIA
IO0 50
Contour interval 20 feet
Elevations referred to cottar of main shaft,
which is IOOO. OO feet (assumed)
+
EXPLANATION
GEOLOGY OF THE C LEVEL, TALC CITY MINE
GEOLOGY OF INTERMEDIATE LEVELS, TALC CITY MINE
GEOLOGY OF THE B LEVEL, TALC CITY MINE
ology by 8 M Peg*
GEOLOGY OF A PART OF THE D LEVEL, TALC CITY MINE
GEOLOGY OF B, C, D AND INTERMEDIATE LEVELS, TALC CITY MINE
STATE OF CALIFORNIA
DEPARTMENT OF NATURAL RESOURCES
UNITED STATES DEPARTMENT Of THE INTERIOR
GEOLOGICAL SURVEY
SPECIAL REPORT 6
PLATE 3
/.' ;.,' rZ' Limonit; cub.s I
VERTICAL SECTION ALONG LINE B-B', TALC CITY MINE
CENTRAL ORE BODY crest of moln rldje
VERTICAL SECTION ALONG LINE C-C', TALC CITY MINE
VERTICAL SECTION ALONG LINE D-D',TALC CITY MINE
EXPLANATION
WEST
OREBODY
Slrollflad dol
VERTICAL SECTION ALONG LINE A-A', TALC CITY MINE
VERTICAL SECTIONS, TALC CITY MINE
EXPLANATION
Altered dolomite
Altered slate and silica rock
Massive dolomite
Contact, showing dip
(Dashed where approximately located}
Fault or shear, showing dip
(Dashed where approximately located)
S<~€0
Strike and dip of beds
X,o
Strike of vertical beds
E B
Vertical shaft
-A3
Pit or open cut
Dump
Underground workings
(Not all shown)
-f
SURFACE GEOLOGY OF THE ALLIANCE TALC MINE AND IRISH LEASE, INYO COUNTY, CALIFORNIA
< iS
ir
a a
a a
U \$ '<Ij sj n 1!
So
+
°5
en
o
z:
^
(T
O
<: <
Z
Q
or
Z
o
3
u.
O
i
ir
<
o
o
cc
UJ
V
o
H
z
■z.
3
~)
o
U.
o
o
o
2
O
>-
h-
-
o
Ul
UJ
2
(J)
^
Q
o
^
1
<
<
h-
O)
2
Ul
<
o
_l
z
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<
_J
O
_1
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CD
BY 8 M PAGE ANO L A WRIGHT SEPTEMBER 1942
SURFACE GEOLOGY OF THE WHITE MOUNTAIN TALC MINE, INYO COUNTY, CALIFORNIA
1 DIVISION OF MINES
OLAF P JENKINS. CHIEF
SW
A
STATE OF CALIFORNIA
DEPARTMENT OF NATURAL RESOURCES
WEST FAULT
UNITED STATES DEPARTMENT OF THE INTERIOR
GEOLOGICAL SURVEY
-I-
T7V3F
a
A13
+
EAST FAULT
vim
CENTRAL FAULT
AND DIKE
SECTION A— A' SOUTHWEST HALF
ROAD TO KEELER
SECTION A — A' NORTHEAST HALF
NE
A'
SPECIAL REPORT 8
PLATE 7
EXPLANATION
Mantle — thick soil , talu
ez
Talc, semi- talc and
intermingled material
•J < \l <
Dike, sill , rhyolite or ande
Massive dolomite
Silica rock
Flinty, dolomitic limestone
Sanded limestone
'1LL1I
approximately located)
No 16 Adit Level
Enfronce to
glory hole
■f
Fault or shear (Doshed
*here approximately located)
GEOLOGIC CROSS SECTIONS
WHITE MOUNTAIN MINE
INYO COUNTY, CALIFORNIA
200 250 FEET
SECTION B — B
SECTION C-C
DIVISION OF MINES
OLAF P. JENKINS, CHIEF
STATE OF CALIFORNIA
DEPARTMENT OF NATURAL RESOURCES
UNITED STATES DEPARTMENT OF THE INTERIOR
GEOLOGICAL SURVEY
SPECIAL REPORT 8
PLATE 8
ADIT NO. 29
EXPLANATION
ADIT NO 13
ADIT NO.8
a 59€3
+
ADIT NO. 20
ADIT NO. 18
Tolc. semi-talc and
intermingled material
Dike, rhyolite or andesite
Mossive dolomite
Silica rock
Flinty, dolomitic limestone
Contact, showing dip
(Dashed where indefinite)
,
Fault, showing dip
(Dashed where approximately lacoled
U, upthrown side. Q.downthrown side)
Fault with variable dip
Fault zone or shear zone
Axis of anticline
Strike and dip of beds
Generalized strike
of contorted beds
^X>
Underground workings
Ore chute
Head of raise or winze
IS
Foot of roise or winze
ADIT NO. 36
ADIT NO. 2
GEOLOGY BY LA WRIGHT AND 6 M PAGE. 1942
GEOLOGIC MAP OF ADITS, WHITE MOUNTAIN MINE
Montie-soii,toius, etc
I °°< I
ESS
Tolc
I- Wl
Contoct, shewing dip
iOasnea nrfwra appro*
Conceoled contact
Fault or shear, showing dip
imotely to cot BO")
, Concealed toutl or shea
Strike and dip of beds
Underground workings
,1 di.
Flinly, dotomitlc limestone
Sandy dolomite
w-
Generalized strike
and dip of beds
Verlicol shaft
Trench or open cut
By L A.Wright and B.MPoge
1942
GEOLOGIC MAP OF THE SOUTH DEPOSIT FLORENCE TALC MINE, INYO COUNTY, CALIFORNIA
Contour interval 20 feet
Initio! elevation assumed to be
5500 feet of A A
DIVISION OF MINES
OLAF P. JENKINS, CHIEF
STATE OF CALIFORNIA
DEPARTMENT OF NATURAL RESOURCES
UNITED STATES DEPARTMENT OF THE INTERIOR
GEOLOGICAL SURVEY
SPECIAL REPORT 8
PLATE 10
+
~SlOo
EXPLANATION
Talc and included matter
Felsite, largely altered to chlorite
Silica rocK
Massive dolomite
Wl
Limestone- stratified
Contact, showing dip
(Dashed where approximately located)
Fault or shear, showing dip
(Dashed where approximately located)
Strike and dip of beds
H B
Shaft at surface
e m
Bottom of shaft
c?
Open cut
Underground workings
Track and dump
By L A. Wright and B M Page
December 1942
SURFACE AND UNDERGROUND GEOLOGY OF THE FRISCO TALC MINE
INYO COUNTY, CALIFORNIA
Contour interval 10 feet
Datum is assumed mean sea level
I DIVISION OF MINES
OLAF P. JENKINS. CHIEF
STATE OF CALIFORNIA
DEPARTMENT OF NATURAL RESOURCES
UNITED STATES DEPARTMENT OF THE INTERIOR
GEOLOGICAL SURVEY
SPECIAL REPORT 8
PLATE II
EX PL A N ATION
Talus ond landslide material
Talc and semi-talc
Granitic rocks with
various inclusions
Dolomitic morble
Contact, showing dip
(Dashed where opproximotely located)
(Dashed where approximately located)
Strike ond dip of beds
Trench
+
Limit of quarry
GEOLOGIC MAP OF
THE WHITE EAGLE MINE
INYO COUNTY, CALIFORNIA
BY L. A. WRIGHT AND B.M.PAGE
1942
Bin chute
+
300 FEET
=3
Contour interval 20 feet
Initial elevation assumed to be
3600 feet at A A
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